Stephen Harper has been in office since January 2006
Canada's governor general, Michaelle Jean, has cut short a trip to Europe to deal with a growing political crisis.
Opposition parties have united in a bid to topple the minority conservative government of Stephen Harper less than two months since a general election.
Mr Harper has indicated he will ask for a temporary suspension of parliament to stop the opposition voting him out.
But if the vote happens and he loses, Ms Jean would ask the opposition to form a government or call a snap poll.
"I think my presence is required in the country," Ms Jean told the Canadian Broadcasting Corporation from the Czech Republic.
"The prime minister and myself need to have a conversation... I have to see what the prime minister has to say to me and what he is actually thinking of doing."
Ms Jean is the representative of head of state Queen Elizabeth II and her role is usually largely ceremonial.
But developments of the past few days have thrust her into the centre of the political storm.
Born in Haiti, emigrated to Canada 1968
Former journalist, documentary film-maker
Appointed September 2005
Speaks five languages: French, English, Italian, Spanish, Creole
The opposition Liberals and New Democrats on Monday agreed to form an alliance, backed by the Bloc Quebecois, saying the government was failing to tackle Canada's economic problems.
They were also angered by Mr Harper's proposals, since rescinded, to eliminate public financing of political parties, a move that would have hit them hard.
Mr Harper's Conservatives were re-elected with a stronger mandate in October, but as they failed to secure a majority, they must rely on the support of the opposition to pass budgets and laws.
The prime minister rounded on his opponents during Question Time in parliament on Tuesday.
"The highest principle of Canadian democracy is that if you want to be prime minister, you get your mandate from the Canadian people, not the separatists," said Mr Harper, in a reference to the separatist Bloc Quebecois.
For his part, the Liberal leader, Stephane Dion, attacked Mr Harper for considering asking the governor general to prorogue parliament, saying it was a dodge to avoid a confidence vote.
"Every member of this House has a received a mandate from the Canadian people...The prime minister doesn't have the support of this House," he said.
The confidence motion is scheduled for 8 December but Mr Harper has indicated he may seek the suspension of parliament until 27 January when the government is set to table its budget.