"I think that Haiti - not withstanding the total devastation wreaked by the four storms there last year - has a chance to escape the darker aspects of its history in the 35 years I have been going there," he said.

'Fragile ground'

The former US president, who was previously the UN's special envoy for tsunami recovery following the 2004 Asian tsunami, visited the island, the poorest country in the Western hemisphere, in March with Ban.

His main tasks will involve improving Haiti's ailing infrastructure and employment prospects in an island with a jobless rate of up to 70 per cent.

During a donor conference held in Washington DC in April, which pledged $353m in aid to the country, Michele Pierre-Louis, the Haitian prime minister, said that the island "could no longer wait" for support.

"We are treading on very fragile ground. If no action is taken now, the consequences will be catastrophic," she said.

'Genuine opportunities'

"I hope that in the process of doing all this, we will continue to elevate awareness of both the pain and the promise of Haiti in the international community"

Bill Clinton, new UN envoy on Haiti

Clinton said on Monday he would ensure the UN was doing "everything we can" to make sure that donor commitments are "aligned as closely as possible with the Haitian programme we have been given".

"We believe there's a lot of economically viable opportunity yet untapped for clean energy and also for energy efficiency, particularly in manufacturing facilities and in [homes]," he said.

"I hope that in the process of doing all this, we will continue to elevate awareness of both the pain and the promise of Haiti in the international community, and [that] there are real genuine economic opportunities there."

Haiti has a long history of political violence and instability, with last year marked by riots over food shortages.

In addition, at least 800 people were killed last year and about $1bn damage was inflicted by four hurricanes that swept through the country.