Malaysia said today it had sent an advance party of 25 military officers to East Timor to prepare for the arrival of about 500 troops and police to help quell an uprising by rebel soldiers.

"Our role will be to assist in ensuring the stability of Timor Leste," Defence Minister Najib Razak said, adding that the deployment would be "open-ended at this stage".

The contingent was originally scheduled to leave late on Thursday, but Najib said he first wanted to see the advance party's report and establish whether the mission would operate under a United Nations mandate.

"It is an issue of cost and also the authority of the UN, whether we are operating as blue berets or we are going on a bilateral basis," he said.

The size of the contingent would be decided after that was established, he said, adding that the advance party was due to arrive in Dili late today and report back to the government on Friday.

"We will determine later. We have put on alert, on standby about 275 men and there are some 200-odd police personnel as well on standby," he said. "They can go at any time now."

"They will not leave tonight. We will wait until we get the full report from our recce team as well as knowing the status of the mission."

Najib said Malaysia responded to the call from East Timor, which is facing its worst violence since independence, for "humanitarian reasons".

"Here is a country that is in trouble and appealing to Malaysia and I think it is only appropriate that there was some response from us," he said.

Australian commandos

An advance wave of some 130 Australian commandos arrived in East Timor Thursday to secure Dili's airport in the first step towards quelling escalating violence between the military and rebel soldiers.

Canberra is planning to send a force of up to 1,300 troops backed by three warships, helicopters and armoured personal carriers.

East Timor has also asked New Zealand and Portugal to send forces. Portugal pledged to send paramilitary police but New Zealand Prime Minister Helen Clark said she first wanted more details.

Violence erupted in Dili last month after 600 soldiers were sacked when they deserted their barracks after complaining of regional discrimination over promotions in the tiny state, which has an east-west ethnic divide.

East Timor, a former Portuguese colony, was invaded in 1975 by Indonesia, which held the territory until 1999, when a vote for independence descended into brutal violence by Indonesia troops and pro-Jakarta militias.

Malaysia also took part in a UN-backed intervention force to stop the bloodshed. The territory was run by the United Nations until independence in 2002.