Green Party Leader Elizabeth May says she has not made a secret deal to support Stephane Dion in the televised debates, but will try to help explain why Canadians need a "Green Shift" carbon emissions plan.

Both the Green Party and Liberals have their own "Green Shift" plans, and May has said the basic idea originated from her own party.

"I think the notion of a backroom pact is such nonsense," she told CTV's Question Period on Sunday.

"Where I agree with him, I'll agree with him. And where I disagree with him -- on issues like NAFTA, nuclear power, some of the economic policies that the Liberals have traditionally espoused -- I will be taking him on in a respectful way, as I will the other leaders."

The Conservatives and New Democrats had initially opposed including May at the debates, but last week they agreed to let her participate after a public outcry. Conservative Leader Stephen Harper had suggested May would merely bolster support for Dion.

"Elizabeth May is not an opponent of Stephane Dion," Harper said at a campaign event in Richmond, B.C., on Sept. 8.

"She is his candidate in (the Nova Scotia riding of) Central Nova, and I think it would be fundamentally unfair to have two candidates who are essentially running on the same platform in the debate."

It's a charge that May has flatly denied. She said the Green Party has a broad platform that covers more than just environmental issues, and should appeal to Progressive Conservatives and Reformers who feel abandoned by Harper's party.

"We appeal to Reformers who ... believe their party was a grassroots democracy and found out that (the Conservatives had) the most top-down autocratic-style of government in Canadian history," she said.

May also said she will not defend Dion and the Liberals in the televised debates. Instead, she said she wants Canadians to fully understand the issues -- even when it comes to Dion's "Green Shift" plan.

The Tories and NDP have maligned the plan, and Dion has been criticized for being unable to clearly and simply explain what he claims is a revenue neutral tax that will reduce greenhouse gases.

"Since it's our plan, the 'Green Shift' plan, I can explain it fully," she said, claiming that Dion was "brave enough" to accept parts of her party's environmental platform.

"I think the fact that I can explain it may be useful to Canadians in making up their minds on how to vote. This is not a contest about who is the best debater ... If you care about Kyoto, if you care about climate action, it's very clear that Mr. Harper is the worst possible choice," she said.

This will be the first time in history the Green Party is included in the televised federal election debates, which are scheduled for Oct. 1 and Oct. 2.