Jose Ramos-Horta, the East Timorese foreign minister, said on Wednesday that the Australian troops were expected to arrive in 48 hours.
"The situation has been calm. I haven't heard reports of a single shot throughout the night," he said.
"But this calm and this quietness is very precarious. There are still tens of thousands of people sheltering in different parts of the city or outside the city.
"There is still palpable fear among many thousands of people, a fear that the violence can break out again."
On Tuesday, clashes between security forces and soldiers who were recently sacked, left two dead.
Alexander Downer, the Australian foreign minister, said he had received a verbal request for assistance from Ramos Horta, and expected a formal request from the government within hours.
"We do not anticipate that either the police or the defence force would have to engage in any hostile activities because... [their arrival] will have an immediate calming effect throughout the country," Ramos-Horta said.
Portugal also said on Wednesday it would send about 120 military police following a request from Xanana Gusmao, the East Timorese president.
And Ramos-Horta said he had asked Malaysia and New Zealand for additional security forces.
Violence first erupted in April, when about 600 soldiers were sacked for desertion after complaining of discrimination.
A rally to support the soldiers in April turned into a riot after security forces opened fire on the crowd. Five people were killed and thousands fled their homes.
A rally to support the soldiers in
April turned violent
On Tuesday, two people died, reportedly including an East Timorese soldier, and five others were injured in separate clashes with rebels. Fighting was also reported near the capital, Dili, on Wednesday.
Both Australia and New Zealand have advised their citizens to leave the country.
The violence has been the worst since clashes erupted between East Timorese and Indonesian militias in 1999, when territory voted for independence.
East Timor, a former Portuguese colony and invaded by Indonesia in 1975 and annexed until 1999, became independent in 2002 following three years of United Nations administration.