Saying they would not follow orders from the U.S. Government, Canadian United Auto Workers union officials refused yesterday to accept further pay cuts designed to save the tottering Chrysler Corp.

The rejection means that only Chrysler's American UAW workers will be involved in a contract renegotiation aimed at paring an additional $260 million in wages from an agreement the union ratified in November.

It also means that, for the first time since 1967, Chrysler workers in the United States and Canada will come under two separate contracts.

The union's renegotiation talks with Chrysler are scheduled to begin this morning.

UAW President Douglas A. Fraser, accompanied by union Vice President Marc Stepp, went to Windsor, Ontario, yesterday morning to try to win Canadian support for the congressionally approved Chrysler rescue plan requiring further wage cuts. They came back the same day, empty-handed.

Frank LaSorda, president of UAW Local No. 444 in Windsor, explained why in a telephone interview.

"We don't believe that any bill passed in the U.S. Congress should be allowed to control the lives of Canadian workers. We can't have a governing body from a foreign country dictating to us. . . . This is something we just can't take," LaSorda said.

Robert White, the UAW's Canadian director, offered similar comments in a news conference following his meeting with Fraser. White said the U.S. mandated concessions would have "horrendous effects" on the 14,000 UAW workers in his country.

A scaled-down UAW contract is needed to secure $1.5 billion in federal loan guarantees for the nation's No. 3 automaker. Congress approved the rescue loan package last month on condition that Chrysler come up with $2 billion more in assorted concessions by its employes, creditors, dealers and suppliers.

The key element of the package is the renegotiation of the UAW's 1979 Chrysler contract, a three-year pact that already contains $203 million in pay concessions designed to help the company steady itself. Congress is asking the union to cut $260 million more from that contract.

Canadian objections to that request seem to be based on more than nationalistic pique.

UAW-Canada leaders said yesterday that Congress has placed them in potential double jeopardy. They said Chrysler officials had already initiated separate talks with the Canadian government. But those talks were scuttled last month when Canadian Prime Minister Joe Clark was forced out of office by a no-confidence vote.

Elections for a new government are scheduled Feb. 18, after which the company plans to renew talks with Canada's political leaders. The country's UAW leaders said they were fearful that, had they gone along with Congress, their government might have required additional wage sacrifices designed to secure Canadian financial aid for Chrysler.

In Detroit, UAW chief spokesman Don Stillman said yesterday that union lobbyists had warned Congress that "trying to get foreign workers to accept the mandate of the U.S. government would be a sticky problem."

Now, he said, the U.S. workers apparently will have to bear that burden alone. However, neither Stillman nor other UAW officials were able or willing to say yesterday what that additional weight will mean in terms of wage dollars lost per worker.

Some union officials said that UAW negotiators are leaning toward raising the $260 million by significantly cutting the number of paid holidays (20 per year through 1982) in the present contract. Other, smaller cuts might come in step increases in wages negotiated last year, they said.

For his part, Fraser said yesterday that he still expects to have an approved, reworked contract with Chrysler before the end of the month.