THE Straits of Malacca and Singapore, and the South China Sea have, for centuries been vital to world trade, as these maritime routes form the shortest link from West to the East.
Malaysia is one of the caretaker states bordering these important international shipping lanes.
These straits are navigated by more than 80,000 vessels a year, dubbed as the second busiest after Dover Strait in Europe.
Malaysia has expressed uneasiness that Aukus would enable Australia to develop nuclear-powered submarines through the trilateral security partnership with the United States of America and the United Kingdom.
Should Malaysia be worried over this development?
The Strait of Malacca is relatively large in breadth in its northern part towards the Andaman Sea and it narrows down forming a funnel-shaped waterway as it flows south into the Strait of Singapore.
As the UN Convention on the Law of the Sea 1982 (Unclos) allows Malaysia and Indonesia to claim territorial seas up to 12nm in the Strait of Malacca, it leaves the strait without any exclusive economic zone (EEZ) or high seas corridor for foreign vessels to exercise freedom of navigation while plying through it, as provided for in Article 58(1) of Unclos.
This also applies to the Strait of Singapore, which entirely falls into territorial seas of Malaysia, Indonesia and Singapore.
As the maritime areas in the southern portion of the Strait of Malacca and the entire length of the Strait of Singapore are part of territorial seas of Malaysia, Singapore and Indonesia, foreign vessels, including military vessels do not possess the right to exercise freedom of navigation.
Nevertheless, Unclos allows foreign vessels to exercise the right of innocent passage. Article 19(1) of the Unclos prescribes that foreign vessels do not need to acquire prior authorisation to sail through territorial seas belonging to another state unless if such passage is prejudicial to the peace and security of the coastal state concerned.
In such a situation, the coastal state may temporarily suspend the navigation of that recalcitrant vessel, as stipulated in Unclos Article 25(3).
Does this mean that Malaysia could suspend the right of transit passage of any nuclear-powered military vessels plying through its territorial sea within the Straits of Malacca and Singapore, should such a passage be deemed prejudicial to Malaysia’s security?
Under international law, the answer is not in the affirmative.
Although parts of the maritime areas of the Straits of Malacca and Singapore are under Malaysia’s sovereignty, Malaysia’s regulatory capacity as a coastal state in governing ships plying through its territorial sea is subjected to the regime of transit passage, not innocent passage, as expounded in Part III of Unclos.
Transit passage regime
When Unclos came into being in 1982, it provided special navigational regime to be implemented in territorial seas, which are part of straits used for international navigation –including the Straits of Malacca and Singapore.