The Canadian government has submitted a parliamentary motion calling for its 2,500 troops in Afghanistan to remain there until at least the end of 2011.
The "confidence" motion, which would extend Canada's Afghan mission by almost three years, is set to be voted on in March and its defeat could trigger early elections.
The motion says the extension is dependent on Nato sending 1,000 extra troops and military equipment to aid the Canadians in Kandahar province - the birthplace of the Taliban.
The issue is controversial and polls have shown that about 50 per cent of Canadians want the soldiers back on schedule.
Seventy-eight Canadian soldiers and a diplomat have been killed in Afghanistan, the majority killed by roadside bombs.
The confidence element of the motion increases the pressure on Canada's opposition Liberal party, which backs the idea of keeping the troops in Afghanistan longer but only if their combat role is ended.
They are expected to oppose the confidence motion, which would bring down the minority government and force early elections.
"The objective is to shift more and more responsibility to the Afghan army," said Peter Van Loan, a government minister, saying that the troops would continue to carry out combat missions for the time being.
"We aren't looking here for permanent bases and permanent stations in Afghanistan. We want the Afghan people to be able to run their own country."
Stephane Dion, the Liberal leader, said his party would propose amendments to the plan, but stressed the combat part of the mission had to end next year.
"If we are ambiguous ... it will be a never-ending mission," he told CNKW radio in Vancouver.
French support
Canada, Britain and the Netherlands have the most troops in the Nato-led International Security Assistance Force (Isaf) in Afghanistan's south, and have faced increasing attacks from a resurgent Taliban forces.
Canadian officials are currently in Paris discussing whether France can send troops. Media reports say France is deciding whether to transfer a 700-strong force.
Last month, a report by a committee led by John Manley, the former Liberal deputy prime minister, urged Canada to keep its troops in Afghanistan but only if bolstered by additional Nato troops.
Stephen Harper, the Canadian prime minister, said he accepted the recommendations.