Actor Matt Damon (second right), Haitian-born singer Wyclef Jean, centre, and former Canadian ambasador to Washington Frank McKenna (right), distribute food to flood victims in Gonaives. (Ramon Espinosa/Associated Press)

Canada's former ambassador to the U.S. joined actor Matt Damon and singer Wyclef Jean on Sunday as they rode in the back of a pickup truck and distributed aid to people in the flood-ravaged Haitian city of Gonaives.

Frank McKenna said he joined in relief efforts, organized by Jean's Yéle Haiti and ONEXONE ("one by one") children's charity, to call attention to a humanitarian crisis caused after one tropical storm and two hurricanes hit the impoverished Caribbean country in the past few weeks.

"What we're seeing is a city that was in abject poverty before this flood and now totally under water, and we see people desperately trying to survive by living on the roofs of their houses," McKenna told CBC News.

He said they handed out basic rations, including cooking oil, rice and beans. But since it's impossible to help everyone who needs it, their most important goal is to provide a boost to international aid efforts.

McKenna, Damon and Jean are encouraging more people to help the United Nations raise more than $100 million US for an estimated 800,000 Haitians in need of aid.

Catching first sight of flooded homes and people living on roofs with all their belongings, Damon was at a loss. "I'm speechless, I can't believe it," he said.

As three men surveyed the destruction, a man on a bicycle followed as far as he could, shouting out, "Wyclef, I love you, Wyclef." Jean acknowledged the fan, but didn't share his happiness.

Folk hero in Haiti

"It's inhumane. I wish there was a word in the dictionary. No human should be living like this," he said.

Damon and Jean later waded through knee-deep floodwaters and climbed a stage outside the Gonaives cathedral, where about 50 people have taken refuge in the choir balcony.

Jean, who lives in New York but remains a folk hero in Haiti, sang briefly and urged crowd to stay calm and organized.

"If you love Wyclef, yell 'help,"' said the singer and founder of the Yéle Haiti foundation.

The crowd surged the stage, and when Jean later tried to leave, people instead swept him out into the streets. Admirers clung to UN trucks as they drove away, some asking for money.

The goal of the effort is to raise money for food, water, tents, blankets, medical supplies and other items for Haiti, the ONEXONE website says.

McKenna was premier of New Brunswick from 1987 to 1997, and ambassador to Washington in 2005 and 2006.