OTTAWA — A campaign to encourage people to fill out the census was slashed because government decided to add two language questions to the form, Industry Minister Tony Clement said Wednesday.

Clement had promised to spend up to $30 million on a campaign to boost response rates to the 2011 census and the new voluntary National Household Survey, which is the government's replacement for the mandatory long-form census.

He told a Commons committee in July that it was important to "pay a price" to get reliable data and protect the privacy rights of Canadians.

But Statistics Canada revealed earlier this week that only half that amount would be set aside in contingency funds for promoting the census and survey.

Now, $10 million will be spent to add two questions on official languages usage to the mandatory short-form census. The government made the decision at the 11th hour after pressure from francophone groups over the summer.

Another $5 million will be spent on extra printing and postage costs associated with sending the new voluntary long questionnaire to more households.

Clement said something had to give once the language questions were added.

"We had to act within a budget, that's part of what we do as cabinet ministers, and when we wanted to add questions and we wanted to reprint, all of those things cost money so I wasn't going to blow the budget to make those changes, so we had to take it out of somewhere," Clement said.

He insists that the government can still do a good job encouraging people to do their civic duty.

"The upshot of it is, can we mount a successful publicity campaign with the money and the answer is yes," Clement said.

The Opposition criticized the rejigging of the census budget.

"Experts have expressed serious concern that the government's incessant fear-mongering on the long-form census will have disastrous effects on Canadians being willing to fill out the short-form census," said Liberal MP Carolyn Bennett, co-author of a private member's bill to revive the long census.

"Now we learn that the government has slashed and reallocated the very budget to persuade Canadians to participate in the census. Will the government stop misleading Canadians about the privacy of the census data, start telling the truth, and restore the mandatory long-form census?"

The Conservative government eliminated the long-form census over the summer, saying it was trying to achieve a balance between the need for reliable data and the right to privacy.

Critics, including the former chief statistician, the Federation of Canadian Municipalities, charities, academic organizations and provincial ministers have all warned that reliable data will be lost by making the long questionnaire voluntary.

Internally, Statistics Canada officials have said they expect only a 50 per cent response rate to the National Household Survey after a first mailout. The agency has said it cannot predict how much information it will be able ultimately to release from the survey.