New York  - UN Secretary General Ban Ki-moon said Tuesday Haiti can break the impasse created by natural disasters and poverty, but it must act because international assistance is time bound.

Ban said in capital Port-au-Prince before leaving for Washington that the UN mission in that country and the United States' relief programme, known as US HOPE II Act, are not indefinite.

"In spite of the recent and severe setbacks, we now have a real window of hope to lift Haiti out of its downward spiral if the Haiti authorities, international community and national and international private sector can rally around a critical path to place the country on the road to economic security," Ban said at a news conference also attended by former US president Bill Clinton.

"There is a growing optimism that Haiti has the assets it needs to break the impasse," Ban said.

Ban and Clinton flew to Port-au-Prince Monday for a one-day intensive talks with the government of President Rene Preval. Ban was to meet with US President Barack Obama at The White House later Tuesday.

US assistance in Haiti offers a "unique and substantial lifeline" to try to reverse the economic degradation in one of the poorest nations in the region, Ban said.

Haiti was devastated by a series of hurricanes last year while it struggled to rebuild from seasonal natural disasters and an economic downturn.

An international donor conference will be held in April to give Haiti a fresh start in breaking the cycle of poverty and natural disasters, Ban said.

Clinton brings his own experience to Haiti through his global initiatives to assist poor countries. He successfully led the recovery programmes in Indian Ocean nations that suffered heavy damage, both physical and economic, from the December 2004 tsunami.

The UN mission in Haiti, first dispatched in 2004, has been assisting Port-au-Prince on security and democratic reform. It is composed of more than 7,000 military and civilian personnel. (dpa)