International police deployed to East Timor in the wake of unrest in May have formally handed over their authority to the United Nations during a ceremony in the capital.

Some 554 police now fall under the control of the new UN mission in East Timor which was set up by the Security Council last month, according to a mission spokeswoman.

Diplomats from Australia, Malaysia and Portugal symbolically placed blue berets on the heads of representatives of their respective police forces serving in the tiny nation at the ceremony attended by about 100 officials.

"You have a double responsibility and priority: to serve the community and to serve your respective countries," Prime Minister Jose Ramos-Horta told the gathering.

Ramos-Horta praised the "outstanding" job done by the foreign police force so far in East Timor, which was plunged into months of political uncertainty after violence among military and police factions left some 21 people dead in May.

UNMIT, which has an initial six-month mandate, is tasked with assisting in elections due next year as well as strengthening the East Timorese police and justice system. Some 1,608 police officers and 34 military liaison officers are to be part of the mission.

The original violence, which saw an estimated 150,000 people in the nation of one million flee their homes in fear for their lives, was triggered by the dismissal of 600 deserting soldiers. Most of the refugees remain in camps, lacking confidence in the security situation.

One of the world's youngest and poorest countries, East Timor became independent in 2002 after voting in 1999 to end 24 years of Indonesian rule. It was administered by the United Nations during the interim period, which quickly scaled down its operations after independence.