The minister was giving evidence at a hearing of the House of Commons committee on industry, science and technology when he admitted that StatsCan, the national statistics agency, had “recommended the status quo”.

Clement (pictured) had previously indicated in press reports that Statistics Canada officials had reassured him that the 2011 census could be managed effectively without forcing some people to fill out the longer version of the form – a statement that prompted the resignation of chief statistician Munir Sheikh, who said in his resignation letter that a voluntary survey “can not” become a replacement for a mandatory census.

At the committee hearing last month Clement said: “Of course, I am aware that Statistics Canada recommended the status quo. It is true and it is important to acknowledge it. But our government chose an approach directed at striking a fair balance between the burden placed on Canadians and the needs of data users. In my opinion, it is a fine balance.”

The Marketing Research and Intelligence Association (MRIA) has written to the government to oppose plans to drop the mandatory long-form census, warning that a voluntary survey will lead to “skewed” and “biased” data being used to formulate public policy.

MRIA says the new voluntary National Household Survey will likely have “a substantially lower” response rate and the resulting data “will be less robust”.

Similar criticisms have come from other quarters, and Clement acknowledged those concerns in his evidence. He said: “We recognise that the information gathered in the long-form census is valuable. However, we also recognise that a balance must be drawn when the government is collecting data under the threat of fines, jail, or both.”

On the issue of response rate, he said StatsCan recognised that the sample size would decrease as the long form becomes voluntary. “We have agreed to send the National Household Survey to 4.5m Canadian households, almost double the sample size from 2006,” said Clement. “This will be the largest survey distributed to the Canadian population in our history.”

Clement has previously argued that the change to a voluntary questionnaire is necessary to answer privacy concerns and that the government “does not believe it is appropriate to force Canadians to divulge detailed personal information under threat of prosecution”.

Beyond the changes to the make-up of the census, the Canadian government said yesterday it plans to introduce legislation in the autumn “to remove threats of jail time for persons refusing to fill out the census and all mandatory surveys administered by the federal government” – though fines can still be levied.