Just one year after it swept into office with a commanding majority, the Conservative government of Canadian Prime Minister Brian Mulroney finds itself in an atmosphere of crisis, buffeted by scandals, Cabinet resignations and attacks and ridicule in the press.

An attention-grabbing dispute over government approval of the sale of allegedly rancid tuna fish led to the resignation of Mulroney's fisheries minister late last month. Two days later, his communications minister quit after coming under investigation for campaign spending irregularities.

Opposition party legislators have attacked Mulroney for the way his government handled two ailing western Canadian banks, whose failures appear likely to cost taxpayers more than $1 billion. And there were allegations recently against another Cabinet member, accusing her of billing the government for personal expenses on two European trips.

Some aides worry that the controversies are subjecting the fledgling government to something worse than scandals -- the devastating effect of laughter and ridicule.

In an interview last week, Mulroney expressed confidence that the troubles would blow over. But, he added, "if you're asking me whether I'd like to do it again, the answer is no."

He said he felt like the Montreal Expos catcher in 1969 who went zero for four as the team lost its 22nd consecutive game. "I feel great," he recalled the catcher as saying after the game, "but I don't think I did too well."

The prime minister said he thought most Canadians were more interested in the improvement in the Canadian economy since he took office and in his efforts at ending the warfare between the federal government and various provinces that had marked the tenure of former prime minister Pierre Trudeau.

Opposition members of Parliament and commentators in Canada's contentious press have reveled in the controversy that some of them refer to as "tunagate." In the rough and often brutal give and take of parliamentary sessions here, they have likened Mulroney's protestations that he was unaware of a decision made by his fisheries minister to the public disclaimers of Richard Nixon during Watergate.

"I remember Richard Nixon, who was an unindicted coconspirator, . . . a very tragic figure in American history," Mulroney responded in one of his many exchanges with foes on the tuna matter. "His problem was that he failed to respond fully and completely to legitimate questions, unlike me, who responded completely before the House and the Parliament of Canada."

Precisely what was wrong with the 1 million cans of tuna fish processed at a plant in New Brunswick has been obscured in the controversy provoked by a television report on the matter by the Canadian Broadcasting Corp.

What is undisputed is that Canadian fisheries inspectors decided the tuna was not fit for human consumption but were overruled by Fisheries Minister John Fraser. When asked by opposition critics in Parliament what was wrong with the tuna -- was it rotten, rancid, tainted or merely smelly? -- Fraser responded that it was a "question of esthetics," a remark that prompted hoots throughout the country.

After the television report, Mulroney ordered the tuna fish off the shelves and later told reporters that it was "pretty damned obvious" it should never have been approved for sale.

Television and newspapers across Canada have had a field day with what they call the case of the "rancid tuna." The day after Fraser quit, the banner headline of the London Free Press in Ontario read, "Fraser Resigns but Mulroney's on the Hook." A critical editorial in the Times-Colonist newspaper in Victoria, British Columbia, was headlined: "The Odor Lingers."

In an Ottawa supermarket, a clerk, asked whether he had removed cans of tuna from the shelves, answered, "Yes, three times for different television networks."

Political combat in Canada is especially fractious because key members of the Cabinet must respond daily to questions raised by the opposition, and the prime minister himself is expected to face the music in the House of Commons at least three times a week.

"I'll confess to you there are moments when I pray for a Rose Garden," Mulroney said, referring to the American system during the interview last week. But he added that the questioning by the opposition is "part of our system and a healthy part of our system. It's unusual, it's probably untidy and occasionally unpleasant, but it's an important part of our system."

After a day of being battered, the prime minister appeared serene and far more confident than some of his aides, who had been shaken by the succession of crises. Mulroney said he was certain he would ride out the storms and he thought that the opposition parties were probably going to help in that matter as they stood perilously close to offending the "doctrine of fairness" of Canadians.

"They will not forgive in this country unfairness or intolerance," he said.

"This is a four-year game," William Fox, Mulroney's press secretary, said. "It's like a football game. There are four quarters," he said.

Old Ottawa hands such as Thomson newspaper chain columnist Stewart MacLeod compared the tuna affair to other Canadian scandals that were damaging in the way they captured public attention. These included a 1956 auditor general's report about horses being on the payroll at military bases.

But as Mulroney labored to defend his credibility on the tuna affair, Communications Minister Marcel Masse announced that he had asked to be relieved because of an investigation of a complaint that he had not reported all his election expenses. Masse said he expected to be exonerated but his resignation heightened the sense of a government under siege.

Meanwhile, opponents pummeled Mulroney about his government's decision to bail out the Canadian Commercial Bank in western Canada in March with a package of government and private aid totaling about $200 million, only to decide early last month that it was beyond salvation.

Mulroney aides estimate that compensations to depositors could end up costing the government more than $1 billion. After the parliamentary outcry over the way the matter had been handled, Mulroney named a Supreme Court justice to investigate.

The next day, a newspaper alleged that another member of Mulroney's Cabinet -- Suzanne Blais-Grenier, secretary of state for transport -- had charged the government for personal expenses during two European vacations she and her husband took this year. She denied the charge but has turned down reporters' requests for proof that she paid the expenses.