Mr Zoeillik visited areas where people are still living in temporary shelters
Haiti is at a "tipping point" after being ravaged in recent weeks by a series of tropical storms, World Bank President Robert Zoellik has warned.
Mr Zoellik, who was in Haiti to see for himself the scale of the destruction, said it "makes your eyes pop".
He also said Haiti was on course to have all its World Bank debts cancelled by mid-2009 once it tackled corruption.
Haiti was hit by two tropical storms in August and September and two hurricanes that left some 800 people dead.
The storms caused nearly $1bn (£618m) of damage, Mr Zoellik said at the end of a three-day visit to Haiti.
"That's a lot for a country of eight million people and there's been a terrible loss of lives.
"The devastation is widespread and it makes your eyes pop."
The western city of Gonaives was left swamped by mud
During his visit, Mr Zoellik flew by helicopter over Gonaives, where floods swept away many houses and left the city deep in mud.
"I sense that Haiti is at a tipping point. It could go either way," he said.
"We have to deal with the immediate needs, to deal with the social instability but there's also a chance to build."
The World Bank announced earlier this month that it would give $25m in additional emergency grants to help rebuild infrastructure.
Mr Zoellik said all Haiti's World Bank debts, which amount to $550m out of a total foreign debt of $1.69bn, could be forgiven by the middle of next year.
This is provided the country meets certain criteria, including addressing corruption and boosting public investment.