Liberal MP Bob Rae says newly released documents show the Conservative government's claim that a voluntary long-form census survey would be statistically valid is "completely untrue."

Liberal MP Bob Rae speaks during a news conference in Ottawa on Wednesday. (CBC)Speaking to reporters on Wednesday in Ottawa, Rae lashed out at Industry Minister Tony Clement for his suggestion in interviews last month that Statistics Canada recommended the move to scrap the mandatory long-form census when emails between the agency and his office show the opposite.

Rae said the chain of emails between Clement's office and the agency on the decision show Clement was trying to "pass the blame" to Statistics Canada.

"He wasn't telling the truth," Rae said. "Mr. Clement knew that in fact the method was not statistically valid."

Clement, the minister in charge of Statistics Canada, has been the government's point man on its defence of the move to scrap the mandatory long form. In an appearance at McGill University last month, Clement said the government had "come up with a way that is statistically valid, that StatsCan feels can work."

But the 200-plus pages of documents show Statistics Canada warned Clement's staffers as early as March that the response rate for a self-administered voluntary long-form census would be less than 50 per cent.

"We know perfectly well that now that StatsCan said exactly the opposite," Rae told reporters.

The documents were compiled at the request of the House of Commons industry committee, which is examining the government's census decision and leaked to reporters on Tuesday.

The chains of emails between the agency, Clement's office and other senior bureaucrats also shed light on the government's influence over Statistics Canada's communication plan around the change.

Clement feels 'alone' in census furor

Industry Minister Tony Clement appears before the House of Commons industry committee in Ottawa in July. (Fred Chartrand/Canadian Press) Former Statistics Canada chief statistician Munir Sheikh resigned after Clement made comments in a Globe and Mail interview in July that suggested Sheikh and the agency recommended to end the mandatory long-form census and replace it with a voluntary survey.

Clement told the House of Commons industry committee last month that the government was solely responsible for the decision.

The minister told the Globe on Tuesday that he did not misrepresent Statistics Canada's position on the voluntary survey, insisting he has been "consistent throughout" and made clear the government was doubling the sample size because the response rate would be lower.

"I know I don’t have very many allies in the media on this. I’m kind of alone out here," the Globe quoted Clement as saying. "All I can tell you is that I do believe it's the right thing to do, and in politics, if you start not doing the right thing because some people criticize you, why would I be wasting my time."

Clement again defended the move, saying Canadians should not be coerced to fill out the census survey with threats of jail time or fines for refusing to divulge personal details to the state.

But Rae said past census results show there has never been a compliance problem, and accused Prime Minister Stephen Harper of using the census changes to wage "guerrilla warfare" against every department of the civil service.

"This has never been an issue for anyone aside from a government that is ideologically bent on undermining the trust that Canadians have in government, and that is fundamentally uninterested in the condition of the people," he said.

NDP Leader Jack Layton, in turn, called Harper "pigheaded" on the move and said he wants the House of Commons to reconvene to debate the issue immediately.

He said he would be calling other opposition leaders to work on a "common approach" to restoring the mandatory long-form survey.

"You've got the broad sweep of Canadian society that feels that having data about who we are, so we can make good public policy, is essential," Layton told reporters in Ottawa.

"It's a bad idea, and it ought to be able to be resolved."

The Liberals, Rae added, would be supportive of the "very simple solution" to keep a required long-form census and remove the penalties for non-compliance.

"We're quite happy to take it out of the law and have a form people respond to in an informative way," Rae said.