Maximum foreign ownership in port operators is 40% according to the WTO Trade Policy Reviews (2014, 2013). For maritime cargo-handling and other port-auxiliary services, the maximum foreign ownership depend on the by-laws or rules of the relevant port authority. For the purposes of the OECD FDIRRI, it is assumed that these services are subject to the same foreign shareholding limitation as for port operators.
"Part IIa - Registry
11. Qualification of Malaysian Ship
(1) Subject to subsection (1B), a ship shall not be deemed to be a Malaysian ship unless it is owned wholly by persons of the following descriptions, namely -- (a) Malaysian citizen; (b) corporation which satisfy the following requirements: (i) the corporation is incorporated in Malaysia; [...] (iv) the majority, or if the percentage is determined by the Minister under subsection (1A) then the percentage so determined, of the shareholding, including the voting share, of the corporation is held by Malaysian citizens free of any trust or obligation in favour of non-Malaysians; and (v) the majority, or if the percentage is determined by the Minister under subsection (1A) then the percentage so determined, of the directors of the corporation are Malaysian citizens.
(1A) The MInister may, by notification in the Gazette, determine -- (a) the percentage of the shareholding for the purpose of subparagraph (iv) of paragraph (b) of subsection (1); and (b) the percentage of the directors for the purpose of subparagraph (v) of paragraph (b) of subsection (1).
(1B) The Minister may, if the thinks it fit, prescribe other requirements in addition to the requirements prescribed in subsection (1).
[...]
Part IIb - The Domestic Shipping Lincensing Board
65A. Interpretation
In this Part, unless the context otherwise requires, "domestic shipping" means the use of a ship -- (a) to provide services, other than fishing, in the Federation waters or the exclusive economic zone; or (b) for the shipment of goods or the carriage of passengers -- (i) from any port or place in Malaysia to another port or place in Malaysia; or (ii) from any port or place in Malaysia to any place in the economic exclusive zone or vice versa. 
[...]
65Ka. Prohibition of Non-Malaysia ships to engage in domestic shipping
(1) No ship other than a Malaysian ship may engage in domestic shipping; (2)  A person not qualified to own a Malaysian ship as provided by section (11) shall not charter or otherwise engage any Malaysian ship for domestic shipping service except under and in accordance with such conditions as the Minister may direct or prescribe 
[...]
65U. Exemption by Minister
Whitout prejudice to any other powers conferred by this Part, the Minister may, by notification in the Gazette, exempt any ship from any of the provisions in this Part or any regulations made hereunder upon such terms and conditions as he may deem fit." (Merchant Shipping Ordinance 1952 [Ord. 70/1952])
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"Merchant Shipping Ordinance 1952 - Exemption from Subsection 65KA(1):
In exercise of the powers conferred by section 65u of the Merchant Shipping Ordinance 1952 [Ord. 70/1952], the Minister exempts non-Malaysians ships from the provisions of subsection 65ka(1) of the Merchant Shipping Ordinance 1952 in respect of the transport of containerized transshipment cargo for the sectors between the Port of Sepangar and the Port of Klang and vice versa, between the Port of Bintulu and the Port of Klang and vice versa, between the Port of Kuching and the Port of Klang and vice versa, between the Port of Sepangar and the Port of Tanjung Pelepas and vice versa, between the Port of Bintulu and the Port of Tanjung Pelepas and vice versa and between the Port of Kuching and the Port of Tanjung Pelepas and vice versa, with effect from 3 June 2009" (Federal Government Gazette, 3 June 2009, P.U. (B) 179).
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"Merchant Shipping Ordinance 1952 - Exemption from Subsection 65KA(1): 
In exercise of the powers conferred by section 65u of the Merchant Shipping Ordinance 1952 [Ord. 70/1952], the Minister exempts non-Malaysians ships from the provisions of subsection 65ka(1) of the Merchant Shipping Ordinance 1952 in respect of cruise services from any port or place in Malaysia to another port or place in Malaysia with effect from 15 March 2012." (Federal Government Gazette, 7 March 2012, P.U. (B) 66).
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[Port operations: no legal documentation found online in English. However, according to the WTO Trade Policy Review of Malaysia, 2014, p. 118, "maximum foreign ownership in port operators is 49%"; in WTO (2023), p. 119: "The maximum foreign ownership in port operations is 40%."]. 
Merchant Shipping Ordinance 1952 [Ord. 70/1952], as amended
Federal Government Gazette, 3 June 2009, P.U. (B) 179.
Federal Government Gazette, 7 March 2012, P.U. (B) 66.
[<a href="https://www.ilo.org/dyn/natlex/natlex4.detail?p_lang=en&p_isn=89550">Ordinance</a>],[<a href="http://www.mot.gov.my/SiteCollectionDocuments/Maritim/Akta-Ordinan-Warta/cruise%20vessel%20exemption%20from%20cabotage.pdf">Gazette</a>],[<a href="http://www.mot.gov.my/SiteCollectionDocuments/Maritim/Akta-Ordinan-Warta/Warta%20Kerajaan-Maritim.pdf">Gazette</a>],[<a href="https://docs.wto.org/dol2fe/Pages/SS/directdoc.aspx?filename=q:/WT/TPR/S292R2.pdf&Open=True">Other</a>],[<a href="https://docs.wto.org/dol2fe/Pages/SS/directdoc.aspx?filename=q:/WT/TPR/S436R1.pdf&Open=True">Other</a>]