Speaking to reporters at the 400th anniversary events in the town of Cupids, Newfoundland, Harper said he was getting tired of the repeated threats to his minority Conservative government, the Canwest News Service reported.
The Conservatives hold 127 of the 308 parliamentary seats, trailed, in order, by the Liberals, Bloc Quebecois, the New Democratic Party and four independents.
"Two of the three opposition parties don't support the government and say we should be defeated," Harper said of the Liberals and NDP. "I think, quite frankly, I'm going to have to make a judgment in the next little while as to whether or not this Parliament can function productively."
The Liberals have had several opportunities to call a non-confidence vote on major issues in recent months such as the federal budget and Canada's combat role in Afghanistan, but party leader Stephane Dion has held back on the challenge.