The four candidates vying to become the next president of the Liberal Party of Canada faced off during their final debate Friday night.

Sheila Copps, Mike Crawley, Alexandra Mendes and Ron Hartling laid out their visions before delegates at the Liberal convention in Ottawa.

During the moderated debate late Friday night they took questions on issues facing their party such as fundraising, the organization of riding associations and leader selection.

"We need to ... be open to new ways of voting," said Copps, who wants the next leader chosen through a "progressive vote." One part of the country would vote first, then another region, over a period of time. She also wants to introduce internet voting and said that the Liberals need to use social media tools to engage young Canadians.

"We need to be on Facebook, we need to be on Twitter," she said.

Copps, a former MP who is a frontrunner in the contest, said Liberals need to spend less time talking to each other and must reach out more.

Crawley, Copps's main rival in the race, said the party needs to do more to give a voice to the membership. He suggested allowing members to submit questions for question period in the House of Commons as one way to engage them.

He agreed that social media tools need to be used to attract young people to politics, so they can get the "instant activism" they seek through other means.

Crawley, a long-time Liberal who was president of the Ontario wing, said Liberals now have a once-in-a-generation opportunity to change their party and to make it a truly modern party.

"We have to seize this opportunity, we cannot let it slip away," he said.

Hartling, who is president of the local riding association in Kingston, Ont., said he has the skills and passion to rebuild the party.

"My style is to listen and to act on what I hear," he told delegates.

Mendes said she also has the experience to fill the role and that she is the person to get the party on the right track to grow its membership and finances.

Around 3,000 delegates are attending the biennial policy convention and will be voting throughout the day Saturday for the new president and other party positions. The winners will be announced Sunday.

There was a fifth candidate in the race for president, Charles Ward, but he withdrew earlier in the day Friday and endorsed Crawley.