A motion calling for the resignation of Environment Minister Rona Ambrose is to be put to a vote today by MPs on the house of Commons environment committee.
The motion from New Democratic MP Nathan Cullen comes at the end of a spring session in which Ms. Ambrose has borne the brunt of opposition attacks.
But the Conservatives are raising the stakes and threatening a fall election should the motion pass.
Conservative Whip Jay Hill confirmed to The Globe and Mail last night that he told NDP House Leader Libby Davies late yesterday that a motion that passes through committee would be considered a confidence matter if the committee report is put to a vote this fall.
Any committee report can be put to a Commons vote if an MP moves what is called "concurrence." If the government is defeated on a confidence motion, it falls and an election must be called.
NDP spokesman Brad Lavigne said his party does not intend to back down. He said "the real question will be what the other opposition parties do." Before the Tories turned the matter into a showdown, the NDP was expecting support from the Liberals and the Bloc Québécois.
The motion contains a long list of criticisms against Ms. Ambrose, including the fact that she refused to attend a smog summit in Toronto and spurned repeated invitations to appear before the environment committee itself.
Some of the most serious complaints are that she does not intend for Canada to meet its obligations under the Kyoto Protocol and has no plan to reduce greenhouse gas emissions.
But Ryan Sparrow, a spokesman for Ms. Ambrose, said the minister is doing well with a difficult portfolio, introducing new pollution laws and taking Kyoto to its "next steps."
"Canadians just made a decision and for the NDP to bring them back to the polls, they're going to have to answer for that," he said.
The NDP move will come as a federally funded report is released calling for Ottawa to signal as soon as possible that it wants deep, long-term cuts in greenhouse gas emissions if it wants the private sector to change its ways.
The National Round Table on the Environment and the Economy report will outline how Canada can slash its greenhouse gas emissions by 60 per cent by 2050 while doubling the size of the economy and quadrupling the exploitation of Alberta's tar sands.
The report, circulated to the news media yesterday and scheduled for release today, strikes a hopeful note that deep cuts can be achieved.
"The first and perhaps most important finding of the analysis is that it can be done, at least from a technological standpoint," it states.
"The chief difficulty in significantly reducing GHG [greenhouse gas]emissions is not the lack of relevant technologies -- rather it is the lack of long-term signals indicating that ongoing GHG reduction will remain a priority," it continues.
The federal round table consists of 15 individuals representing industry, government and academia who meet four times a year to discuss environmental issues and propose policy options.