OTTAWA - Ontario and Quebec have launched a formal complaint against the federal government's decision to axe the long-form census, calling the move a "mistake" that will have serious consequences.

Cabinet ministers from both provinces have written to federal Industry Minister Tony Clement, requesting he reinstate the long census survey "as soon as possible."

The two-page letter dated September 27, obtained by The Canadian Press, argues forcefully that the census decision will hamper provincial support for education, innovation and economic development.

The lack of data from the census long form will also further impair labour mobility and governments' understanding of the country's labour market, the ministers said.

The letter is signed by Ontario Minister of Training John Milloy, Quebec Education Minister Line Beauchamp, and Quebec Employment Minister Julie Boulet.

Some provinces spoke out against the federal government's census move during the summer, but the formal complaint from Ontario and Quebec escalates their opposition.

"We believe that the decision by the federal government to eliminate the census long form was a mistake and that it will impact negatively on the provision of services to the people of our provinces," it says.

"We therefore urge you to reverse this course of action as soon as possible."

The federal Conservatives have been on the hot seat all week over their move last June to eliminate the mandatory long census and replace it with a voluntary survey.

The three opposition parties backed a motion Tuesday to revive the mandatory long-form census. The Liberal motion, scheduled for a vote Wednesday afternoon, was demanding the return of the mandatory long questionnaire, minus the threat of jail time.

But Clement has said plainly that his government will not respond to the motion if it passes the Commons.

Clement said Tuesday that the decision to replace the census with a voluntary survey, mailed to more households, was a way to strike a balance between the privacy rights of Canadians and the need for the information by government policymakers and outside groups.

"Let me put this question ... to any member of the Liberal-Bloc or NDP coalition partners: If someone in one of your ridings does not want to complete the 40 pages of personal, private questions ... is it the appropriate government response to harass them until they relent and comply?" Clement said in the Commons.

Clement and other Conservative colleagues raised points during the debate that have been contradicted in other arenas or do not match public information.

"It's absurd to put honest citizens in prison when they refuse to say how many bedrooms they have and I even dare to say what kind of cereal they eat in the morning," Quebec Tory Steven Blaney said.

Previous censuses have not included a question on breakfast cereals -- nor the number of bathrooms in a house or what somebody is reading, two other questions Conservatives have publicly fumed about.

Clement stated that some census workers were hired to work in their own neighbourhoods, "meaning that your neighbour can know some of your most personal and intimate information."

But the Office of the Privacy Commissioner has said Statistics Canada brought in a series of changes nearly 20 years ago to ensure census workers worked outside their neighbourhoods. Census documents also offer respondents the option of mailing back their forms or else asking for a different census representative if they're not comfortable with who comes to their door.

A spokesman for Clement later said the information the minister was referring to was relayed to Conservative MPs from constituents over the summer.

Saskatchewan MP Lynne Yelich, minister of state for western economic development, during the debate raised the case of a woman in her province, Sandra Finley, who is being prosecuted for failing to fill out the 2006 census.

In fact, Finley's opposition to the census was not related to the intrusiveness of the questions, but the fact Statistics Canada had purchased technology from defence manufacturer Lockheed Martin. She told The Canadian Press in July she was not satisfied with the steps taken by the Conservatives.

The census issue was also being debated a few streets over on Tuesday inside a Federal Court hearing, where the Federation of Francophone and Acadian Communities is arguing the elimination of the long census will violate provisions of the Official Languages Act. It is asking the court to bring back the mandatory long-form questionnaire as soon as possible.

The federal government made its case to Justice Richard Boivin on Tuesday that nothing in the act directs the government to use census data as it works to nurture official language minority communities in Canada. It also argued that there is no evidence the new voluntary survey won't provide usable data.

The court has heard that Statistics Canada cannot make changes to the 2011 census process past the middle of next week, because of a complicated administrative schedule.

Bennett also has a private member's bill to bring back the mandatory long form that is expected to hit the Commons by mid-October. She argues the government would have a hard time blocking the bill because it would actually save money to reinstate the long form.