Canada's 2,000 troops in the Kandahar region have been committed only until February, but Prime Minster Stephen Harper has continually said that Canadians could remain in Afghanistan for years to come, the Toronto Star reported.
"We are bringing humanitarian assistance to the Afghan people and we are assisting the Afghan forces with the building of security in their own country," Harper said in the Commons last month.
Opposition parties confirmed they had been approached about the Tory idea to get Parliament's backing for a renewed commitment.
"We agreed to do a debate on Wednesday," said Mylene Dupere, spokeswoman for Liberal Leader Bill Graham. "The debate will be followed by a vote."
Defense Minister Gordon O'Connor said the continued commitment of troops makes other military involvements impossible.
The New Democrats have been urging the Tories to send a military force to Darfur.