Individual foreign shareholdings in Air New Zealand are capped at 10%, per company statute, unless prior consent is granted. 
"1.6 Definitions: In this Constitution, unless the context otherwise requires: [...]
Kiwi Shareholder" means Her Majesty the Queen in right of New Zealand;[...]
"New Zealand Business" means:
(a) A person exempted from the requirement for consent provisions of the Overseas Investment Act 2005 by regulation 48 or regulation 49 of the Overseas Investment Regulations 2005; [...]
"New Zealand National" means:
(a) Any New Zealand citizen, [...]
(d) Any New Zealand Business which has been approved by the Board for the purposes of this definition;
(e) Any company, or other body corporate, that is established in New Zealand and has its registered office in New Zealand and that is substantially owned and effectively controlled by persons coming within any of paragraphs (a) to (d) of this definition;
[...]
3.4 Limitation on Ownership by Non-New Zealand Nationals: No person who is not a New Zealand National may hold or have an Interest in Equity Securities which confer 10 percent or more of the total Voting Rights for the time being unless the prior written consent of the Kiwi Shareholder has been given to such holding or Interest, and any such consent may be given on such terms and conditions as the Kiwi Shareholder thinks fit.[...]" (Constitution of Air New Zealand Limited (25 September 2019), Clauses 1.6 and 3.4)
Constitution of Air New Zealand Limited (25 September 2019), Clauses 1.6 and 3.4
[<a href="https://p-airnz.com/cms/assets/PDFs/airnz-constitution-25sep2019.pdf">Statute</a>]