Conservative Leader Stephen Harper came to the defence of Gerry Ritz on Thursday, a day after the agriculture minister came under fire for making jokes about the listeriosis outbreak.

While campaigning in the strategically vital province of Quebec, Harper called Ritz's comments about the outbreak that has been linked to the deaths of 17 Canadians ''completely inappropriate."

But Harper dismissed pressure from opposition parties for him to apologize personally on behalf of the government and fire Ritz, noting the minister had already offered his unreserved apologies.

"I think he’s been doing a good job on this file and applaud him for apologizing completely and forthrightly," Harper told reporters in Trois-Rivières.

All three opposition parties called for Ritz's resignation Thursday, as did family members of those who died from the listeriosis outbreak.

The controversy again forced the Conservatives into damage control mode during their campaign for the Oct. 14 federal election after earlier gaffes by campaign staff threw the Tories off message.

The Canadian Press reported on Wednesday that Ritz made the controversial remarks at an August conference call with scientists, bureaucrats and political staff.

Fretting about the political dangers of the crisis, Ritz reportedly quipped: "This is like a death by a thousand cuts. Or should I say cold cuts."

When mistakenly told about a reported death in Prince Edward Island, Ritz said: "Please tell me it's [Liberal MP] Wayne Easter." It has now been determined that no one has died from the listeriosis outbreak in P.E.I.

'Shows insensitivity to families'

Harper said Thursday that Ritz "was working very, very hard" at the time he made the comments.

"I think this story is obviously very embarrassing for him, very unfortunate," Harper said.

"But should not detract from the good work that he has done to get on top and understand this matter, to improve the system, and to communicate publicly with Canadians and to make sure that government officials are all doing their job."

Ritz had initially received praise during the crisis last month for immediately returning to Ottawa and handling the federal response, although opposition critics decried Health Minister Tony Clement's decision to remain in Denver for the U.S. Democratic national convention.

Easter, the Liberal agriculture critic, told CBC News Thursday morning that his party called for Ritz's resignation in September over his handling of the outbreak, not for his wisecracking.

Easter also called on Harper to apologize to families who have been affected by listeriosis.

The joke Ritz made about Easter is in keeping with "a pattern of the Harper government in which anyone who disagrees with them is going to be treated with disrespect and attacked," he said.

"But the real terrible point here is that this shows insensitivity to families who lost loved ones and to the seriousness of the issue itself."

Ritz showed 'lack of respect,' families say

The mother of 36-year-old Kristen Hicks, who died in an Alberta hospital Aug. 14 of listeriosis, said she's angry about Ritz's comments.

"I think Mr. Ritz showed very poor judgment and a lack of respect for the Canadians he's representing," Mary Hicks told CBC News.

Hicks questioned Ritz's scripted apology without allowing questions, saying it made her feel that "public safety was secondary to his wish to remain in office."

Also Thursday, the son of a Saskatchewan woman who contracted the same bacteria strain was offended when he learned of the remarks.

"If Harper is the right kind of person to run this country, he's got to do the right thing and get rid of this minister. Simple as that," said Dennis Schroh, whose 82-year-old mother Elizabeth Schroh died Aug. 24.

"For sure, I was a Tory. Now this is going to change me. No doubt about it," he told the Canadian Press.

Elizabeth Schroh's death is still under investigation to determine whether listeriosis was a contributing or underlying factor in her death.

Ignatieff accuses Tories of 'callous incompetence'

Meanwhile, Liberal deputy leader Michael Ignatieff immediately struck out at Harper over Ritz's comments during his first national campaign appearance with Stéphane Dion in Toronto.

"This is a government who at a time when Canadians are dying of listeriosis has an agriculture minister making cheap and offensive cracks," Ignatieff told the crowd of Liberal candidates and supporters.

"That is not leadership; that is callous incompetence. A real leader would fire Gerry Ritz."

The call for Harper to dismiss Ritz was immediately echoed by NDP Leader Jack Layton, who said Canadians are already tired of "weeks of inaction" from the Conservative government on the listeriosis crisis.

"And then when his agriculture minister jokes about it, what do we get but excuses?" Layton said at a campaign appearance in Winnipeg Thursday. "I say that if Stephen Harper was a strong leader, he would take action now."

The latest controversy has drawn comparisons to an earlier tempest in the campaign over comments made by Conservative communications director Ryan Sparrow.

The party suspended Sparrow indefinitely after he sent an e-mail to a reporter suggesting comments made by the father of a Canadian soldier who died in the Afghanistan mission were politically motivated. Sparrow immediately apologized.

Harper personally apologized to Dion in the first week of the campaign after the Tory party's website briefly featured a puffin defecating on the Liberal leader's shoulder.