The federal government does not need a formal parliamentary vote to implement the extension of Canada's Afghanistan mission, Prime Minister Stephen Harper said Friday.

Assigning a training and technical mission — as opposed to a combat mission — is within the authority of the prime minister, he told reporters during the G20 summit in Seoul.

Canadian troops will remain in Afghanistan in a non-combat role after 2011, helping to train and support the Afghan army, Prime Minister Stephen Harper says. (Dene Moore/Canadian Press)

"My position is if you're going to put troops into combat, into a war situation, I do think for the sake of legitimacy … the government does require the support of Parliament," he said.

"But when we're talking simply about technical or training missions, I think that is something the executive can do on its own."

Harper said he is open to a debate in the House of Commons if the other parties have something to add. But he said no vote is necessary.

Harper noted that the Liberals have been in favour of extending the Afghan mission in a non-combat capacity that would include training. The current mission is set to expire in 2011.

But Liberal Leader Michael Ignatieff said Friday his party has "had no contact" on the extension other than "a phone call or two" between Foreign Affairs Minister Lawrence Cannon and Foreign Affairs critic Bob Rae.

"Everybody wants to be sure that the mission that the government has defined is doable, is achievable," Ignatieff said. "We want to know what it costs. We want to know who we're doing this training with. We want to know what the objectives are.

"At the moment, the government gives the impression that they're kind of making it up as they go along and I don't think that's good enough."

The NDP said MPs should get to vote on the issue and accused Harper of a flip-flop.

"Stephen Harper made a solemn commitment to bring the troops home next year, but he has again failed to live up to his words," said NDP Leader Jack Layton in a statement.

"We are demanding the prime minister bring this new extension to the House of Commons for public debate and a vote," he said.

CBC News reported earlier this week that the extension would include up to 1,000 military members to train Afghan soldiers and police officers. The number includes up to 750 trainers and at least 200 support staff.

More than 150 Canadian troops have been killed since Canada's Afghan mission began in 2002.

U.S. grateful for Canadian trainers

In the U.S., Assistant Secretary of State Philip Crowley said his country is "grateful for Canada's ongoing contribution" to the mission in Afghanistan.

"We, the United States, have been encouraging a number of countries to add trainers to help with the development of Afghan national security forces," Crowley told reporters in Washington on Friday.

He said the U.S. and Canada had discussed finding ways to help Afghanistan "take responsibility for its own security."

U.S. President Barack Obama is facing increasing pressure to reduce the country's combat role in Afghanistan dramatically due to costs.

"We are mindful of the real threat we face," a Council on Foreign Relations task force said in a report. "But we are also aware of the costs of the present strategy. We cannot accept these costs unless the strategy begins to show signs of progress."

The Obama administration is to begin a review of its Afghan strategy next month. There are about 100,000 American military personnel in Afghanistan.

With files from The Associated Press