A Conservative senator is urging the government to go back to the drawing board on its proposal to quadruple the fees for seeking a criminal pardon.

Every year, thousands of Canadians apply for pardons in order to get a job, pass security clearances and travel. Right now a criminal record suspension costs $150, after a December 2010 hike from the previous fee of $50, but the government is moving to a cost-recovery model for pardons and wants to charge all applicants $631.

Ontario Conservative Senator Bob Runciman said he thinks the National Parole Board should consider the complexity of each case when calculating fees.

"I think there's an inherent unfairness in the approach the parole board is taking in recommending to Parliament, and hopefully we can change that," he said.

Processing a pardon for shoplifting is more straightforward than processing a pardon for someone with a long criminal record or someone who was convicted of arson or assault, for example.

Denis Ladouceur, the parole board's director for clemency and pardons, testified Thursday about the process before a group of senators studying the fee increase.

"If it's an indictable offence, then the act compels my staff to do more exhaustive verifications," he told the committee on legal and constitutional affairs. "We need to go back to when the offence or offences occurred — the nature of the offence, the gravity of those offences."

Senator suggests tiered approach

Runciman said he'd like to see an approach where there's "three or four tiers based on the level of the crime committed."

Francis Scarpaleggia, the Liberal public safety critic, is open to the idea of a tiered approach.

Top 10 pardoned offences List of which offences led to the most pardons from 2000-2010.

"Maybe that's the kind of nuance we need when we're looking at this issue," Scarpaleggia said.

The NDP's justice critic said his party opposes any fee increases.

For the government's part, a spokesman for Public Safety Minister Vic Toews said calculating fees on a case-by-case basis would be time-consuming and make the pardons process more expensive.

A pardon doesn't erase a conviction, but it allows people who have completed their sentences and shown they are law-abiding to have their criminal record "kept separate and apart" from other criminal records, the parole board says.

Public consultations were held on the fee increase earlier this year. During the process, 1,084 people offered their opinions. Only 12 people approved of the change, with the rest opposing it.