As Canada prepares to ring in its 150th anniversary, Gov. Gen. David Johnston says there's room to discuss Quebec's role in Canada and its signature on the Constitution — despite the prime minister's categorical refusal to reopen the debate.

"Canada is an experiment that is evolving continuously and continuously in the face of both domestic and external events," Johnston said during an interview at Rideau Hall with CBC Radio's The House.

"I would say that those are matters appropriate for continual debate. The wonderful thing about this country is that we don't shy away from debate and discussion. I think we are prepared to put our challenges as well as our opportunities on the table."

Earlier this month, Quebec Premier Philippe Couillard announced plans to start a cross-country dialogue on Quebec's role in Canada, with the possibility of carving out a spot for Quebec's place within the 1982 Constitution.

But Prime Minister Justin Trudeau made it clear he wants no part of it, telling reporters "we are not opening the Constitution."

Johnston said the willingness for frank discussion and compromise is part of Canada's political culture going back to Confederation 150 years ago.

The Queen signs Canada's constitutional proclamation in Ottawa on April 17, 1982 as Prime Minister Pierre Trudeau looks on. (Ron Poling/Canadian Press)

"Our history has shown that we have found ways to achieve a degree of common ground. We are a nation that avoids putting ourselves in a position where we get at extremes and warring with one another, but constantly finding accommodation," he said.

"Canada in 1867 was built on that kind of accommodation, with a number of the partners at the beginning saying, 'My, this is a pretty risky and doubtful experiment.' And a couple of the would-be partners saying, 'We're not going to try that,' but came in a few years later," Johnston said.

"I think that's very much the Canadian way of you don't look for a perfect resolution of an issue, but you are prepared to examine it and to work constructively to find solutions."

Johnston's time as the Queen's representative in this country is coming to an end this fall, when Trudeau will appoint his successor.