Mr Vieira de Mello said he would leave New York at the end of next week to take up his new post as head of the administration overseeing the territory's transition to independence.

Mr Vieira de Mello said the creation of a credible system of justice would be one of his top priorities and he called for reconciliation between all sides in East Timor.

His UN administration will have to build houses, re-establish basic services, help create a democratic system and oversee the return of hundreds of thousands of displaced people to their homes.

BBC UN correspondent Mark Devenport: "Mr Vierrra de Mello wouldn't put a timescale on the completion of his job"

The UN has appealed for nearly $200m over the next nine months to fulfill its task.

Talking to journalists at the UN headquarters in New York, Mr Vieira de Mello said his administration would work closely with the east Timorese.

'No superstructure'

Untaet will work closely with Xanana Gusmao

"We've been consulting with the East Timorese almost none stop and we will be working, I repeat, very, very closely with them on the ground," he said.

"We will not be a superstructure that will attempt to impose itself on the Timorese people and on their representatives, on the contrary we are there to strengthen them, to help them to take the affairs of their country into their own hands," he added.

When asked how long it would take to prepare East Timor for independence, he said "I do not have a crystal ball" and asked for patience.

Maybe in several months he could answer the question, he said.

From Kosovo to Timor

The return of refugees will be a major task

Mr Vieira de Mello, a 51-year old Brazilian diplomat, was appointed on Monday as head of the UN Transitional Authority in East Timor (Untaet).

He is the UN's top official for co-ordinating humanitarian aid. He set up the UN civilian administration in Kosovo before handing over to Bernard Kouchner in July.

Security Council Resolution 1272, adopted unanimously by the 15 council members, gives Untaet, as the new mission will be known, the power "to exercise all legislative and executive authority including the administration of justice".