Fighting in East Timor's capital Dilli has eased after Australian commandos secured the airport, according to Australia's defence minister.
Brendan Nelson told Australian radio on Friday: "With the 220 or so soldiers we already have on the ground a significant degree of stability has come to East Timor and Dili overnight. Over the next 24 to 48 hours you will see the remainder of the 1,300 troops being deployed roll out."
Nelson said: "I fully anticipate that will have a calming effect ... but in the end if we do see people who are not responding to lawful requests from Australian Defence Force personnel we will use whatever level of force is required to see that they are disarmed and do not threaten the life and safety of innocent people."
East Timor, which is one of the world's poorest countries but has potentially lucrative oil and gas reserves, requested international help to quell the violence on Wednesday.
Meanwhile, the Australian and East Timorese governments have agreed on the terms of engagement for some 1,300 Australian soldiers sent in to restore order in the fledgeling nation, John Howard, the Australian prime minister, said.
The agreement was obtained early on Friday during talks between Australian military and foreign ministry officials and Mari Alkatiri, East Timor's prime minister; Xanana Gusmao, the president; and Jose Ramos-Horta, the foreign minister.
But even before the terms of engagement were set, 130 Australian commandos had flown in to secure the airport in East Timor's capital, Dili, and other soldiers landed overnight by military transport plane as violence threatened to escalate into civil war.
Fighting, sparked by the East Timorese government's decision to sack almost half the country's military after they went on strike to protest against poor conditions, worsened on Thursday when at least nine people were killed and 27 wounded.
The deaths came when army elements attacked the Dili police headquarters and, after a negotiated ceasefire, opened fire on unarmed police being escorted out, a UN spokesman said.
At least six people had been killed in Dili before Thursday after protests by the sacked military policemen late last month spiralled into violent clashes with government forces.
Alexander Downer, the Australian foreign minister, said the agreed terms of engagement gave the Australian troops "a very broad mandate" to act.
"When it comes to people running around the street and using guns and machetes and so on, the task will be for our military to make sure that sort of behaviour doesn't continue," he said.
"That won't be easy for them but they will try to achieve that."
Both Howard and Downer said it was essential that Alkatiri's government negotiate with the rebel troops.
Howard was also critical of the government of Alkatiri, which has been branded as autocratic and too inflexible in dealing with the army revolt and issues of discrimination between the ethnically distinct easterners and westerners.
He said: "The way in which the country has been governed in the last few years has left a lot to the be desired."
"The government obviously has lost a lot of authority and confidence," Howard said.
"The real challenge in East Timor is to get a government that has the confidence of the local people."
Downer, for his part, suggested that the peacekeeping mission could drag on for months.
"Whether that will take weeks or whether that will take months it's still too early to say ... it could go into months rather than just weeks."
Meanwhile, the US on Thursday praised Australia for deploying soldiers to help quell violence in East Timor and said it was providing logistical support as needed.
"We welcome Australia's timely and decisive response to this crisis," State Department spokesman Sean McCormack said.
"Our military forces have been working closely with Australian forces and are providing US support as requested," McCormack said in a statement. "This includes military airlift to assist in positioning Australian forces."
In other developments, Kofi Annan, the UN secretary-general, said in a statement on Thursday in Hanoi that he was sending a special envoy to Dili to assess the situation.
Annan had requested urgent UN Security Council approval for military assistance, but the council put off action after Russia argued that more information was needed, diplomats said.
Portugal has said it will send 120 military police to help in the security effort.
Malaysia has postponed its deployment of 500 military and police personnel. Najib Razak, Malaysia's deputy prime minister, said it was seeking clarification about the mission.
Australia led a UN-backed force in 1999 to quell violence after East Timorese voted for independence from Indonesia. An estimated 1,000 people died in that violence, blamed mostly on pro-Jakarta militia backed by Indonesian military elements.
UN peacekeepers left a year ago and the UN mission of 130 administrators, police and military advisers was scheduled to finish in East Timor on May 20, but its term was extended for a month after the recent riots.