Foreign investment in legal service firms is only allowed in the provision of services in relation to international law or home country law, and if carried through a partnership with at least one registered Bruneian advocate and solicitor. 
"ANNEX I - SCHEDULE OF BRUNEI DARUSSALAM
Sector: Business Services
Sub-sector: Legal services
Obligations Concerned: National Treatment (Article 9.4 and Article 10.3), Senior Management and Boards of Directors (Article 9.11), Market Access (Article 10.5)
Measures: Legal Profession Act (Chapter 132)
[...] 
Description: Investment […]
1. A foreign national or service supplier may not supply legal services in Brunei Darussalam except in relation to international law or home country law.
2. A foreign national or service supplier may not establish an enterprise for the supply of legal services in Brunei Darussalam in relation to international law or home country law, except through a partnership with at least one registered Bruneian advocate and solicitor. ” (ANNEX I - SCHEDULE OF BRUNEI DARUSSALAM, Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP))
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"PART II - ADMISSION OF ADVOCATES AND SOLICITORS
Qualifications and procedure for admission
Qualified persons. 
3. (1) A person shall be a qualified person for the purposes of this Act if, subject to the provisions of subsection (3), he — (a) is a barrister-at-law of England or Northern Ireland or a member of the Faculty of Advocates of Scotland; (b) is a solicitor in England or Northern Ireland or a Writer to the Signet, law agent or solicitor in Scotland; (c) has been in active practice as an advocate and solicitor in Singapore or in any part of Malaysia; or (d) is a barrister, solicitor or who is a barrister and solicitor of a Supreme Court of any Australian State or Territory. 
(2) A person who is — (a) a citizen of Brunei Darussalam; or (b) a permanent resident,  on the date of his petition for admission shall, notwithstanding  subsection (1), be a qualified person for the purposes of this Act if he has obtained such alternative qualification as may be prescribed.
(3) A person who is not, on the date of his petition for admission, either a citizen of Brunei Darussalam or a permanent resident, shall only apply for admission if, in addition to satisfying the requirements of subsection (1), he has been in active practice in any part of the United Kingdom, in Singapore, in any part of Malaysia, in any Australian State or Territory or in any other country or territory or part of a country or territory in the Commonwealth designated by the Attorney General by notice in the Gazette for at least 7 years immediately preceding such application.
[...]
Ad hoc admission. 
7. (1) Notwithstanding anything to the contrary contained in this Act, a Judge may, in his discretion, admit to practice for the purpose of any one case any person who satisfies the requirements either of paragraph (a) or of paragraph (b), that is to say — (a) a person who holds Her Britannic Majesty’s Patent as Queen’s Counsel; and who — (i) does not ordinarily reside in Brunei Darussalam but has come, or intends to come, to Brunei Darussalam for the purpose of appearing in the case on instructions of an advocate and solicitor; and (ii) possesses special skill and qualifications for the purpose of the case whether or not such special skill and qualifications are available in Brunei Darussalam;  (b) a person who is entitled to practise before the High Court in Malaysia, Singapore or Hong Kong or in such other Commonwealth country as the Chief Justice may specify; and who — (i) does not ordinarily reside in Brunei Darussalam but has come, or intends to come, to Brunei Darussalam for the purpose of appearing in the case on instructions of an advocate and solicitor; and (ii) has not been admitted under this section in respect of more than 2 other cases in the current calender year; and (iii) possesses special skill and qualifications for the purpose of the case which are not otherwise available in Brunei Darussalam. 
(2) Any person applying to be admitted under the provisions of this section shall do so by originating motion verified by an affidavit of the applicant or of the advocate and solicitor instructing him stating the names of the parties and brief particulars of the case in which the applicant intends to appear. The originating motion and affidavit shall be served on the Attorney General, the other parties to the case and such other persons as may be prescribed. At the time of such service the applicant shall pay a fee of $100 to the Chief Registrar.
[...]
Declaration by Chief Justice that there are sufficient advocates in Brunei Darussalam. 
12. (1) Notwithstanding anything contained in this Act, if the Chief Justice shall be of the opinion that the number of advocates practising in Brunei Darussalam is sufficiently adequate to serve the needs of the community he shall by notice in the Government Gazette so declare. (2) At any time after a declaration under subsection (1) has been made and until such declaration is revoked — (a) no person other than a national of Brunei Darussalam shall be entitled to be admitted as an advocate or to obtain a provisional licence under section 8; (b) His Majesty the Sultan and Yang Di-Pertuan in Council may direct that the name of any advocate on the roll who is not at the expiration of the period of 6 months next following the publication of such declaration or at any time thereafter ordinarily resident in Brunei Darussalam shall be deleted from the roll.
[...]
PART IV -PRIVILEGES OF ADVOCATES AND SOLICITORS 
Privileges of advocates and solicitors. 
17. (1) Subject to the provisions of any written law, advocates and solicitors shall have the exclusive right to appear and plead in all Courts of justice in Brunei Darussalam.
[...]
Qualifications to practise. 
18. (1) Subject as hereinafter provided no person shall practise as an advocate and solicitor or do any act as an advocate and solicitor unless — (a) his name is on the roll; (b) he has a valid practising certificate; and (c) he or the firm of advocates and solicitors of which he is a member or the advocate and solicitor or firm of advocates and solicitors by which he is employed maintains a place of business in Brunei Darussalam suitable for the carrying on of the practice of an advocate and solicitor or a firm of advocates and solicitors, as the case may be, and a person who is not so qualified is in this Act referred to as an “unauthorised person”.
[...]
No unauthorised person to act as advocate and solicitor. 
19. (1) Any unauthorised person who — (a) acts as an advocate and solicitor or an agent for any party to proceedings or who, as such advocate and solicitor or agent or  in  any other capacity (other than as a party to an action in which he is himself a party), issues out any writ, summons or process, or commences, carries on, solicits or defends any action, suit or other proceeding in the name of any other person or in his own name in any of the Courts in Brunei Darussalam or draws or prepares any instrument relating to any proceeding in the Courts in Brunei Darussalam; or [...] shall be guilty of an offence and shall be liable on conviction to a fine of $1,000 and to imprisonment for a term of 6 months.
(2) Without prejudice to the generality of subsection (1) any unauthorised person who either directly or indirectly — (a) draws or prepares any document or instrument relating to any immovable or movable property or to any legal proceeding; or (b) takes instructions for or draws or prepares any document or instrument on which to found or oppose a grant of probate or letters of administration; or (c) draws or prepares any document or instrument relating to the incorporation or formation of a limited company; or (d) on behalf of a claimant or person alleging himself to have a claim to a legal right writes, publishes or sends a letter or notice threatening legal proceedings other than a letter or notice that the matter will be handed to an advocate and solicitor for legal proceedings; or (e) solicits the right to negotiate, or negotiates in any way for the settlement of, or settles, any claim arising out of personal injury or death founded upon a legal right or otherwise, shall, unless he proves that the act was not done for or in expectation of any fee, gain or reward be guilty of an offence under this subsection.
[...]
Sections 18 and 19 not to extend to arbitration proceedings
20A. (1) Sections 18 and 19 shall not extend to - (a) any arbitrator or umpire lawfully acting in any arbitration proceedings; (b) any person representing any party in arbitration proceedings; or (c) the giving of advice, preparation of documents and any other assistance in relation to or arising out of arbitration proceedings except for the right of audience in court proceedings. 
(2) In this section, "arbitration proceedings" means proceedings in an arbitration which - (a) is governed by the Arbitration Order, 2009 (S 3412009) or the International Arbitration Order, 2009 (S 3512009); or (b) would have been governed by either the Arbitration Order, 2009 (S 3412009) or the International Arbitration Order, 2009 (S 3512009) had the place of arbitration been Brunei Darussalam.
[...]
PART VIII MISCELLANEOUS AND GENERAL
 Law Society of Brunei Darussalam [S 40/03] 
Authority to establish Law Society. 
62. (1) His Majesty the Sultan and Yang Di-Pertuan in Council may by order — (a) establish a body representative of the legal profession in Brunei Darussalam to be called the Law Society of Brunei Darussalam; [...]
(2) Without prejudice to the generality of subsection (1), an order made under that subsection may — [...] (d) require that no advocate and solicitor shall practise as such unless he is a member of the Society.[...]"(Legal Profession Act, Chapter 132, as amended)
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"Qualification to practise as sole proprietor or in partnership.
43. (1) No advocate and solicitor, who was admitted as an advocate and solicitor after the commencement of this Order, may practise as an advocate and solicitor on his own account or in partnership unless he — (a) has, since being admitted as an advocate and solicitor, been employed for not less than 3 continuous years or for 3 years out of a continuous period of 5 years in the practice of an advocate and solicitor in Brunei Darussalam; or (b) has been employed as a legal officer in the judicial or legal service of Brunei Darussalam for not less than 3 continuous years or for 3 years out of a continuous period of 5 years. 
(2) The Council may, with the approval of the Chief Justice, shorten any period referred to in sub-paragraph (1)(a) or (b) if it is satisfied that the advocate and solicitor has gained substantial experience in law in Brunei Darussalam or elsewhere. 
(3) Subsection (1) shall not apply to an advocate and solicitor who practises in partnership with any advocate and solicitor who has been in active practice in Brunei Darussalam for not less than 3 continuous years or for 3 years out of a continuous period of 5 years. [...]" (LEGAL PROFESSION (LAW SOCIETY OF BRUNEI DARUSSALAM) ORDER, as amended)
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"Alternative qualifications. 
2. The following qualifications are hereby prescribed as alternative qualifications for the purposes of subsection (2) of section 3 — (a) the Certificate of Legal Practice issued by the Qualifying Board pursuant of section 5 of the Legal Profession Act, 1976 of Malaysia; (b) degree in law conferred by the Universiti Islam Antarabangsa of Malaysia.; (c) degree in law conferred by the Universiti Kebangsaan Malaysia; (d) degree in law conferred by the Universiti Islam Sultan Sharif Ali. [...]" (LEGAL PROFESSION (ALTERNATIVE QUALIFICATIONS) RULES, as amended)
ANNEX I - SCHEDULE OF BRUNEI DARUSSALAM, Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP)
Legal Profession Act (Chapter 132), as amended
LEGAL PROFESSION (LAW SOCIETY OF BRUNEI DARUSSALAM) ORDER, as amended
LEGAL PROFESSION (ALTERNATIVE QUALIFICATIONS) RULES, as amended
[<a href="https://www.mfat.govt.nz/assets/Trade-agreements/TPP/Annexes-ENGLISH/Annex-I.-Brunei.pdf">CPTPP</a>],[<a href="https://www.agc.gov.bn/AGC%20Images/LAWS/ACT_PDF/Cap132(06).pdf">Act</a>],[<a href="https://www.agc.gov.bn/AGC%20Images/LAWS/ACT_PDF/Cap132subO1(06).pdf">Order</a>],[<a href="https://www.agc.gov.bn/AGC%20Site%20Pages/The%20Laws%20of%20Brunei%20-%20L.aspx">Rule</a>]