Malaysia has been shifting west instead of the usual east since the huge December earthquake that produced a deadly tsunami, with Langkawi island moving as much as 18 centimetres, a report said today.

Survey and Mapping Department director general Hamid Ali told the New Straits Times that the southern tip of Johor on the Malaysian mainland had shifted two centimetres to the west.

The Sunda Plate on which the peninsula sits normally moves east by three centimetres every year, but the seismic event was now dragging it in the opposite direction, he said.

"At present, the change is not significant enough to require a new map to be drafted," Hamid told the daily.

"We do not know exactly when the movement of the peninsula will stop, but estimate it could be another 18 months before the Earth's crust settles," he said.

Hamid said another two major earthquakes in the quake-prone region could cause another substantial shift in the Malaysian peninsula.

Malacca Straits affected too

His figures were obtained from the Malaysia Active GPS Systemnetwork of global positioning stations in 18 locations around the country, he said.

Sixty-eight people were killed by the Dec 26 tsunami in Malaysia, most of them on the island of Penang. More than 180,000 people were killed around the region.

Malaysia suffered less than its neighbours because most of its mainland peninsula was shielded from the killer surge by Indonesia's Sumatra, which bore the brunt of the disaster.

The 9.0 magnitude earthquake on Dec 26 was so powerful it made the Earth wobble on its axis and permanently altered the regional map, possibly shifting some small islands as much as 20 metres, US geophysicists have said.

The Malacca Straits, one of the world's busiest shipping lanes which runs between Singapore, Malaysia and Indonesia, has also changed in depth by up to one to two meters at certain points, the Malaysian navy has said.