About US$270 million of that amount has begun to arrive, but most of it has been made available only in recent weeks, and its impact remains imperceptible for many Haitians.

'That the mission turns out well is vital in order to show the world that not only the developed countries can lead peacekeeping and peace-building missions,' said Cesar Mayoral, Argentina's representative on the UN Security Council.

'What is clear is that if the donors don't give the money, the mission is going to fail.'

More than 10 months after the UN mission began, myriad armed groups continue to hold sway as the nation teeters towards local polls scheduled in October and national elections in November.

The mission has launched a pilot disarmament scheme, but fewer than 90 weapons have been collected nationwide, according to the UN Development Programme.

A Philippine peacekeeper was shot dead last week at Cite Soleil, a desperately poor Port-au-Prince slum still controlled by armed gangs four months after UN troops occupied the neighbourhood.

Meanwhile, the mission has been unable to kindle dialogue between the interim government of Prime Minister Gerard Latortue and supporters of former president Jean-Bertrand Aristide, who was escorted from the country by US Marines amid an armed revolt in February last year.

Leaders of Mr Aristide's party, which continues to be the nation's dominant political force, have said they will not participate in elections unless there is an end to repression.

And despite being mandated to support efforts to 'protect and promote human rights', abuses committed by the police continue unchecked.

According to a report last month published by Harvard Law Student Advocates for Human Rights, the mission has been far less proactive in reforming the police, protecting civilians and ensuring human rights than previous missions in other nations.

'The peacekeeping mission continues to ignore not only the spirit but even the explicit prescriptions of its mandate,' report co-author Benjamin Litman said.

To the peacekeepers' credit, they have won praise for leading relief efforts after a devastating tropical storm last September and for preventing political violence from spreading out of control.

'There is a profound consensus among the members that we are doing well, that we are doing right,' Brazil's UN ambassador Ronaldo Mota Sardenberg said.

The Haiti mission is the first one led by a group of Latin American countries, a sign of growing political co-operation in the region, especially among the left-leaning presidents of Brazil, Argentina, Uruguay and Venezuela.

Some of the Latin American members of the mission complain that peacekeeping efforts have not been accompanied by sufficient aid or commitment to development and human rights from wealthy nations.

'We think development and human rights need to happen at the same time as security, but the problem is some members on the security council want to prioritise security,' Mr Mayoral said.

But other council members say the slow arrival of aid is typical of peacekeeping missions.

'There is nothing particular to Haiti about slow rates of disbursement,' said Adam Thomson, Britain's deputy permanent representative on the security council.

'You're not going to get international aid organisations willing to give until you have a basic level of security, and then it takes time to think about what kind of development you're going to do.'