In 2004, Indonesia, Singapore and Malaysia launched a plan to co-ordinate patrol of the strait, with each nation monitoring its own waters and sharing information. The proposal was a step short of joint patrols, where security agents from one state chasing a pirate could cross over into the territorial waters of another state.

In the past, Indonesia and Malaysia have brushed off offers of support from the international community, citing the issue of sovereignty, but last year the shipping lane had become dangerous enough for insurers Lloyd's of London to deem it a high war-risk area.

This year, Singapore and Indonesia announced co-ordinated air patrols and the advisory was lifted. But this has not diminished concern in the international community.

Piracy has given rise to concerns of possible terrorist attacks; security experts say attackers might use an oil tanker as a "floating bomb".