NEW WESTMINSTER, B.C. — The federal New Democrats want Canada to take a lead role in any UN mission to stop the bloodshed in Sudan's Darfur province, even if that means scaling back its commitment in Afghanistan.

NDP Leader Jack Layton pointed to a weekend poll that suggested public support for Canada's Afghan mission is wavering.

A majority of those polled opposed Canada's effort there, compared with a similar poll in March that found only about 40 per cent against the mission.

Layton said a major Canadian commitment to a UN mission in Darfur, where at least 180,000 people have died and millions are refugees because of a bitter civil war, would likely get much broader public backing.

"Our view is that this is exactly the kind of peacekeeping role that Canadians have always supported,'' Layton said Sunday. "Canada invented the concept of UN-led peacekeeping forces under (then diplomat Lester) Pearson'' in the 1950s.

Sudan's government reached a peace deal with the main insurgent group on Friday.

Liberal Senator Romeo Dallaire, the former general who led the doomed UN peacekeeping mission in Rwanda, has called for Canada to play a lead role in a proposed 20,000-member UN peacekeeping force.

Canada has about 100 Canadian soldiers in Darfur acting as advisers to 7,000 African Union troops, which are also using borrowed Canadian armoured vehicles.

Layton acknowledged it's debatable whether Canada's thinly stretched military can handle large deployments in both Darfur and Afghanistan.

"We've heard varying reports out of our military regarding our capacities here,'' he said. "So that is, of course, one of the key questions to be asked.

"But I think that Canadians would want us to be in Darfur. That sentiment is found right across the country.''

About 2,200 Canadian troops are involved in efforts to root out Taliban insurgents in southern Afghanistan. The military has suffered a string of recent casualties there.

The Conservative government has affirmed Canada's commitment but Layton wants a full parliamentary debate on the Afghan mission before it's renewed next February.

Liberal defence critic Ujjal Dosanjh, whose party launched the Afghan mission when it held power, said it's premature to talk about curtailing the effort.

"Those questions should be asked and those discussions should take place at the time the government brings it back before Parliament for renewal or extension,'' he said.

The armed forces' chief of defence staff will advise the government whether the military can play a major role in Darfur while remaining in Afghanistan, he said.

"I don't want to pass judgment on it,'' he said. "I know that we are capable of doing two missions, not necessarily of the same strength and of the same kind.''

NDP defence critic Dawn Black, whose riding Layton visited, said it's unlikely the armed forces can make the necessary commitment to a Darfur mission and maintain its forces in Afghanistan at current levels.

"There seems to be a difference of opinion as to whether we can do both,'' she said. "Romeo Dallaire thinks we can put some troops into Darfur.

"But I think to meet the kind of commitment the UN's asking for in Darfur, it's not likely that we can do that with what (Defence Minister Gordon) O'Connor has said, (that) we're fully extended already into southern Afghanistan.''

Department of National Defence officials were unavailable for comment on Sunday.

Black said that once Canada fulfils its commitment in Afghanistan in February, "we may want to look at returning to a more traditional kind of work that we could do and do very well in Darfur.''

But while it's not as intense as Afghanistan, Darfur would be far from the popular image of blue-bereted Canadians standing between warring factions, said Dosanjh.

"I don't believe Darfur would be a traditional peacekeeping role if we are to disarm the Janjuweed,'' he said, referring to government-backed militias held responsible for much of the killing.

"That doesn't mean we shouldn't take it on. We should.''

Layton also blasted Prime Minister Stephen Harper's recent budget and the government's unwillingness to discuss amendments.

"Mr. Harper's government seems to be largely incommunicado,'' he said. "They don't seem to want to talk, at least with our party.''

The New Democrats are proposing changes that would restore child-care commitments made by the previous Liberal government, funding for the Kelowna accord to help aboriginal communities, environmental initiatives and post-secondary education.

But Layton acknowledged getting the Tories to respond will be hard when the Bloc Quebecois has already promised to support the budget.

"I am frankly shocked that (Bloc Leader) Gilles Duceppe and the Bloc Quebecois is supporting this budget,'' he said. "This budget betrays all of the progressive things the Bloc Quebecois always said that they supported.''

Noting Premier Gordon Campbell's angry statement in the B.C. legislature last week criticizing the Tories for abandoning the Kelowna accord, Layton said provincial premiers and the public need to pressure Ottawa to revive the agreement.

"Canadians don't find it acceptable that First Nations are living in Third World conditions in many places across this country.''