federal judge ruled today that New York Gov. Hugh Carey's order last week canceling a rugby match Tuesday between the South African Springboks and an American team was unconstitutional, and he prohibited the governor from carrying out the directive.

Judge Howard G. Munson agreed with arguments by the Eastern Rugby Union and the American Civil Liberties Union that the match, protested by opponents of the South African system of apartheid, had been transformed from a sports contest into a political event.

As such, it falls under the First Amendment, he ruled. "However repugnant the views expressed, they deserve the constitutional protection of this court," he said.

Assistant state attorney general Peter Yellen said New York would seek a reversal of Munson's injunction Tuesday morning from the federal appeals court in New York City.

"The game is on," said Tom Selfridge, president of the Eastern Rugby Union and a coordinator of the Springboks' American tour.

Opponents of the match promised demonstrations at Albany's Bleecker Stadium, and late today were arranging for busloads of protesters to come here from New York City.

The Springboks arrived in this country one week ago in preparation for a match in Chicago last Saturday.

Denied several Chicago-area sites, the Springboks eluded protesters early Saturday morning, boarded vans and traveled 65 miles to Racine, Wis., where they easily defeated a midwestern all-star team before protesters could disrupt the match.

The Albany game had been in doubt since last Tuesday when Carey, citing threats to public safety, ordered it canceled.

In court today, Yellen said state police sources had predicted that "rampant violence would occur not only in Bleecker Stadium, but the violence would spread to the surrounding community as well . . . .

"Participation in a rugby game is a sporting event and is not protected by the Constitution . . . the governor has broad authority to see that public safety is maintained."

Rugby union attorney Richard Walsh said Carey "has a right to protect the people by calling out the National Guard or the militia. He does not have the right to protect the people by banning public assembly."

Lanny Walter, the lawyer for the Capital District Coalition Against Apartheid, argued that "this game is seen by black people as condoning by the city and state of the most vicious form of racial discrimination in the world."

But he was interrupted by Munson, who asked if the United States Olympic hockey team's playing against the Soviet Union in the 1980 Olympics amounted to a condoning by the hockey players of the system of government practiced in Russia.

Munson said he was rejecting contentions by Carey that there was insufficient time to call out the National Guard, should that prove to be necessary, or that the move would be too expensive.

The Springboks, who arrived here Sunday night to angry chanting by about 80 demonstrators, remained under heavy police guard today. The third and final match of their tour is planned Saturday at an undisclosed site in the Northeast.