The meeting had aimed to raise $125m over the next two years to help rebuild the country's infrastructure and create new jobs.
However, Pierre-Louis told the Reuters news agency that Haiti needed up to $1bn in aid to support Rene Preval, the Haitian president, in his plans to revive the economy.
Pierre-Louis earlier told the donor conference of about 30 nations and organisations that Haiti remained "on fragile ground" following hurricanes that devastated its infrastructure and food riots last year.
"If no action is taken now the consequences will be catastrophic."
Michele Duvivier Pierre-Louis, Haitian prime minister
"If no action is taken now the consequences will be catastrophic," she said.
Haiti, the Western hemisphere's poorest nation, has a long history of political violence and instability, with last year marked by riots over food shortages.
Hillary Clinton, the US secretary of state who attended the conference and who is to visit Haiti later this week, pledged $57m from the US, telling the conference that Haiti "is on a brink of either moving forward with the help of the collective community or falling further back".
The World Bank also said it would grant Haiti an extra $20m in aid this year and is working to speed up the country's debt cancellation, Robert Zoellick, the bank's president said.
"This additional allocation will raise to $80m the new funding that the World Bank Group expects to approve for Haiti for the next two years," he said.
Al Jazeera's Teresa Bo, reporting from Gonaives in Haiti, said 80 per cent of Haitians are living in poverty with three million affected by food shortages.
While some organisations such as the World Food Programme have feeding centres in the country, their funding runs out in June and they are concerned where future money will come from.
|More than 800 people died in a series of
hurricanes in Haiti in 2008 [AFP]
Haitians are also hoping international organisations will play a more important role in improving their living conditions as many people do not trust the government, she said.
At least 800 people were also killed last year and about $1bn damage was inflicted by four hurricanes that swept through the country.
Last month the Brussels-based International Crisis Group said donors at the conference should provide $3bn over the next several years to help Haiti's economy, reduce its vulnerability to natural disasters and maintain access to basic services.
Meanwhile Clinton is to meet Preval on Thursday for talks on "stability, security and assistance", the US state department said on Tuesday.
She will then travel to the Dominican Republic, which shares the island of Hispaniola with Haiti, where she will meet Leonel Fernandez, the president, before flying to Trinidad and Tobago for the Summit of the Americas.