Agriculture Minister Gerry Ritz, seen at a news conference in Ottawa on Sunday, is facing calls for his resignation in the wake of the listeriosis outbreak. (Sean Kilpatrick/Canadian Press)

The Liberal party is calling for the resignation of Agriculture Minister Gerry Ritz, accusing him of staging a coverup over changes to food safety inspections.

"Whether he misled Canadians, whether he is incompetent, we don't know. But clearly he contradicted himself," Liberal Leader Stéphane Dion told reporters on Thursday after wrapping up a caucus retreat in Winnipeg.

But speaking at a news conference in Ottawa, Ritz rejected calls for his resignation, insisting that no cuts were made to the Canadian Food Inspection Agency and that more money, in fact, had been allocated to the department.

The call for Ritz's resignation comes a day after Prime Minister Stephen Harper promised an independent investigation will be launched into the deadly outbreak of listeriosis that sparked a nationwide recall of meat products.

The Liberals claim that under the Tories, a new inspection system was implemented that diminished the role of food inspectors and inspection of food.

"Starting March 1st, a change has been made that put our inspection situation where inspectors are more inspecting paper than meat. And under the circumstances, because this change has been covered up, the minister cannot stay the minister," Dion said.

Dion said Ritz had told Canadians that Tory government documents outlining changes to the food-inspection regimen were just a discussion paper.

But the Liberal leader said when the changes, which transferred more responsibility for regulation to industry from the Canadian Food Inspection Agency, were implemented March 31, Ritz tried to hide them.

Dion added that Harper's pledge for an independent probe into the listeriosis outbreak was a pre-election ploy. He said Harper can deflect questions about the issue of food inspection safety by saying a probe will be launched and that he can't comment.

Ritz repeated Thursday that just because a number of options were laid out, it doesn't mean they were going to be implemented.

"In order to identify, strategically, where your strengths and weaknesses are, you lay the whole road map out. You look through it and you say 'We need to expand on this, we need to cut that because it's not hitting the target. You need to reallocate that.' That's what we did. That was the nature of that strategic review documentation.

"Certainly everything was out there on the table, But simply because it was on the table, doesn't mean we were intending to cut or move things around."

Paul Mayers of the CFIA also took issue with the Liberal's dismissive characterization of the paperwork done by inspectors.

"We do not view that important scientific documentation to be simply paperwork. It is a fundamental element of an effective inspection process," Mayers said

He said an even split between reviewing scientific information and records related to a plant's performance and the physical inspection of the facility is fundamental to the overall inspection process.

With files from the Canadian Press