The Malaysian navy will re-chart the Malacca Straits, one of the world's busiest shipping lanes, in case the depth of the narrow channel was changed by the huge earthquake which struck off Indonesia last month, local media reported today.

The narrow waterway, which separates peninsular Malaysia from the Indonesian island of Sumatra and links the Indian Ocean with the South China Sea, is used by some 50,000 ships a year carrying a third of world trade and half its oil supplies.

The navy's hydrographic survey team will spend several months re-charting the strait, with the depth along the designated shipping lane top priority, a Maritime Department official told the Malay Mail.

Meanwhile, ships have been asked to use their echo sounders as a precautionary measure while navigating the strait, particularly near the shallow One Fathom Bank, Malaysia