Mr Harper's party controls a little more than one-third of parliament

Mr Harper will begin the new session on 16 October with a speech outlining the priorities for his minority government.

If opposition parties reject his agenda, the government will fall and elections will follow immediately.

One key poll issue would be Canada's continuing military involvement in Afghanistan, analysts say.

There has been rising public concern in Canada about the number of troops killed in the conflict.

Since 2002, some 70 Canadian soldiers and one diplomat have died there.

Canada has about 2,500 troops in Afghanistan and forms the core of Nato operations in the province of Kandahar.

Throne speech

Mr Harper's minority Conservatives have been in office since January 2006.

But they hold only 125 seats out of 308 in parliament and have needed the support of the three opposition parties.

MPs were due to return on 17 September but Mr Harper announced that he was asking the Governor General Michaelle Jean to delay the new session of parliament until October.

Calls are growing for a clear end to Canada's Afghan mission

At the start of the new session, Mr Harper will lay out his legislative agenda in what is called a throne speech.

If MPs vote against the speech, Mr Harper's government will fall.

"I'm pleased to report that Canada is united, our government is clean and our economy is strong. Now it's time to launch the next phase of our mandate," Mr Harper said in a statement.

"I invite the other parties to join with us to make the second session even more successful than the first."

The Liberals and the separatist Bloc Quebecois have both indicated that they oppose any plans to extend Canada's Afghan mission beyond its scheduled end of February 2009.

The Bloc Quebecois has said it will vote against Mr Harper if his speech does not specifically promise that Canadian troops will return on time.

The New Democratic Party is calling for the troops to be brought back immediately.