The environment again took centre stage at the House of Commons Tuesday as the Tories and Liberals continued to challenge each other's credibility on the issue.

The parties blasted each other's environmental records for a second day as each tried to claim the honour of being the greenest party. The debate on the environment has heated up as recent polls suggest the issue is the top priority for Canadians.

Liberal Leader Stéphane Dion led off question period by praising his previous government's 2005 budget, quoting Green party Leader Elizabeth May, who at the time called it the "greenest budget since confederation."

He slammed Harper for cutting the environmental projects in the budget, accusing the prime minister of being a "climate change denier."

"The only person in this House of Commons denying something is the leader of the Liberal party, who is denying his own record on the environment," Harper said.

Harper slammed the Liberals' plan, quoting the former environment commissioner as saying "it was not up to the task of meeting the Kyoto obligations."

Deputy Leader Michael Ignatieff also raised the Kyoto environmental accord, calling on the government to meet its international obligations.

Environment Minister John Baird suggested Ignatieff himself was unclear on Kyoto, and used a past comment by Ignatieff to fire back.

"I think our party has gotten into a mess on the environment," Baird quoted Ignatieff as saying. "As a practical matter of politics, nobody knows what Kyoto is or what it commits us to."

The Tories have said that Canada has no chance of meeting its emissions targets under the Kyoto accord and must set more realistic goals for reducing greenhouse gases.

The international agreement requires Canada to cut its greenhouse gas emissions to six per cent below 1990 levels by 2012. But since 1990, emissions have gone up, with the latest figures showing an increase of almost 30 per cent.