The only purpose of Stéphane Dion's carbon-tax plan is to spend taxpayer money and not to reduce Canadians dependency on fossil fuels, Prime Minister Stephen Harper charged Thursday.

In another attack on the Liberal Green Shift proposal, Harper rejected the notion that the plan, which calls for a tax on emissions in order to reduce the use of fossil fuels by Canadian industries and homeowners, will be revenue neutral or temporary.

"The purpose of Mr. Dion's carbon tax is to raise money for the federal government so that he can spend it," Harper told reporters as he wrapped up a two-day caucus planning session in Quebec.

"That is the only reason a politician ever puts in a new tax, and whenever a politician puts in a new tax, he says either it's temporary or it's revenue neutral. This tax will be neither temporary nor revenue neutral. No other tax has ever been.

"Mr. Dion needs money. That's why he wants the tax."

Harper pointed to his own plan to force industry through regulations to reduce greenhouse gas emissions.

"If you want industry to reduce emissions, you ask industry to reduce emissions. If what you really want is money for the government, you impose a tax and that's why Mr. Dion is doing it."

Dion has spent the summer trying to sell his plan, which will levy $15.4 billion in new taxes on Canadian industries that produce high carbon emissions. The higher prices for energy people would face would be offset by broad-based tax cuts, according to the plan.

He has also challenged Harper to a debate on his carbon-tax policy, a challenge Harper has dismissed.

In a speech on Wednesday, Harper in turn challenged Dion to stop delaying the current work of government with futile election threats unless he is prepared to force a vote.

Following on that theme, Harper said Thursday that the Tories will be pushing ahead with their legislative agenda and that the minority government will be holding confidence votes in the Commons this fall.