MONTREAL - The Bloc Quebecois says it's got a compromise solution to the census spat — and it involves replacing jail sentences with lesser penalties.

Leader Gilles Duceppe says he's hoping he might convince Prime Minister Stephen Harper to reconsider his plan to scrap the mandatory long-form census form.

He says the government can keep the mandatory long-form census, and still do away with the threat of prison.

He says the government could simply withhold services — like a passport or Employment Insurance — until people complete their census form.

"There are rights — and there are also responsibilities — for citizens," Duceppe told reporters Tuesday.

"We can tell people, 'Well, if you refuse, certain government services won't be provided to you for as long as you refuse.' A passport, for instance. Employment Insurance, for instance. . .

"That could be an alternative. We'll see. We're open to all suggestions, as long as the census remains in place."

There's no shame, Duceppe says, in admitting when you've made a mistake and he hopes Harper might do just that.

The prospect appears unlikely. The census decision has drawn out a number of critics but the prime minister has given no indication of being swayed by them.

A prominent constitutional lawyer's early assessment is that Duceppe's idea could easily withstand legal scrutiny.

Montreal lawyer Julius Grey said there are all sort of things the government could do to enforce census compliance. Withholding government services is one option.

"It depends what you want to withhold," Grey told The Canadian Press.

"Obviously you can't foresee every single case but a passport, yes. There's been a case this year in Quebec in which the principle of withholding a passport for a deadbeat dad has been upheld."

He wasn't sure about withholding Employment Insurance because "there would be an issue of survival. It depends to what extent." Grey said pressure could be applied, such as delaying payment.

"Of course, as soon as you filled it out, they'd pay you (Employment Insurance) so I suppose it might be constitutional," he said.

"Each particular thing that you're withholding would have to be looked at but in principle Mr. Duceppe's suggestions are workable."

Grey has argued a number of high-profile human rights cases over the years but is perhaps best known for his battles against Quebec's language laws. He has in the past mused about possibly running for the NDP but has never become directly involved in partisan politics.