UNIVERSAL CITY, Calif. (AP) _ About 25,000 demonstrators, some lugging crosses, urged mass boycotts of ''The Last Temptation of Christ'' upon its release today, and at least one major theater chain has decided against showing the film.

The movie opens in nine major cities at the height of a nationwide fundamentalist furor sparked by Christians who say it is blasphemous in its portrayal of a Jesus Christ tempted to abandon his divinity.

In New York City today, about two dozen demonstrators picketed in front of the Ziegfeld Theater, some shouting at the hundreds of film-goers who formed a line that wrapped around the block for a matinee showing.

''We see it as an attack on morality and traditional family values,'' said Rabbi Yosef Friedman, who carried a sign reading, ''Rabbis Protest Mockery of Any Religion.'' ''We feel these people who are mocking Christianity today would also be willing to mock Judaism.''

''WarGames'' director John Badham joined Warren Beatty and Michael Mann at the Directors Guild of America today in support of the film.

''We owe a debt of gratitude to this group of somewhat misguided zealots. The film now will be seen by a lot of curiosity seekers,'' Badham said. ''What is not terrific is their effort to rewrite the Bill of Rights.''

An estimated 25,000 protesters jammed the streets around Universal Studios Thursday, adding their voices to a chorus of protest that has stretched from the studio lot to the halls of Congress.

''A lot of impressionable people who would see this ... will receive a totally skewed, biased, and blatantly false portrayal of the person who is nearest and dearest to our hearts - our savior Jesus Christ,'' said the Rev. Paul Crouch, president of Trinity Broadcasting.

Newton, Mass.-based General Cinema Theaters decided against showing the movie after company executives screened it this week. The company - the nation's fourth-largest movie chain with 1,338 screens in 318 locations - offered no explanation for its decision.

In Maryland, Delaware and North Carolina, newsletters and petitions are being circulated in churches urging their members to persuade theaters not to book the movie. The owners of Oregon's two largest theater chains have said they will not show the film, as did the 44-screen Douglas Theater Co. chain in Nebraska.

And in Boston, Cardinal Bernard Law urged his archdiocese's Roman Catholics to boycott the film because it is ''morally offensive and repugnant to Christian belief.''

''One way to be heard is by not going. Another way is to write the producers,'' Law wrote in the archdiocesan weekly paper.

The movie, directed by Martin Scorsese and distributed by Universal, opens to the public today in Los Angeles, Chicago, Washington, San Francisco, Seattle, Minneapolis, New York, Montreal and Toronto. An invitation-only screening Thursday in Montreal drew about 30 peaceful protesters outside the theater.

Last week, the studio suddenly advanced the release of the film by six weeks, giving its opponents less time to organize threatened boycotts and, perhaps, taking advantage of the current publicity.

In Thursday's protest, buses carrying thousands of Christians rolled into the Universal parking lot, backing up traffic for a mile on the nearby Hollywood Freeway and on roads around the headquarters of MCA Inc., Universal's parent company.

Many demonstrators lugged wooden crosses. Others, with children in tow, carried hand-printed signs reading ''Boycott Blasphemy'' and ''The Greatest Story Ever Distorted.''

Opponents of the film are enraged by Scorsese's portrayal of Jesus as an ambivalent savior. In a hallucination while dying on the cross, Christ imagines abandoning his divinity to live as an ordinary man, and fantasizes about sex with Mary Magdalene.

Most of the film's antagonists have not seen ''Last Temptation'' and base their enmity on reports from the small number of clergy who have viewed it.

Scorsese has defended his film, saying he wished to create a story that would provoke people to think about Jesus as a man confronting temptation. He said the film should be considered art translated from a novel, not an interpretation of the Gospels. The film is based on the 1955 novel by Greek author Nikos Kazantzakis.

Willem Dafoe, the actor who portrays Jesus Christ in the film, said today that he is baffled by protesters' complaints.

''No, I don't understand, I don't understand. I just think this is a beautiful, powerful, positive film. Some people that for the most part haven't seen it are coming out against it - that I don't understand,'' he said in an interview on NBC-TV's ''Today'' program.

While reactions from clergy across the nation have been largely negative, some have been more tolerant.

Beth Cox, summer minister for the Fairfax Unitarian Church in Virginia, said Christ could have been tempted by the sensual.

''Jesus was man and divine,'' Ms. Cox said. ''I would think that the human side of him would have those thoughts.''

Yet other members of the clergy suggested that the best thing to do was not to make much ado about the motion picture.

''We find the film offensive, but we're not going to turn out the troops to march on theaters,'' Monsignor William Reinecke, chancellor for the Catholic Diocese of Arlington, Va. ''We don't want to play it up.''

Among the participants in Thursday's demonstration were the Rev. Donald Wildmon, executive director of the American Family Association of Tupelo, Miss., and Bill Bright, president of the San Bernardino-based Campus Crusade for Christ.

Bright has offered to raise $10 million to buy and burn the film, and Wildmon has urged a nationwide boycott of MCA.

Conservative Reps. William E. Dannemeyer, R-Calif., Robert K. Dornan, R- Calif., and Clyde Holloway, R-La., added their denunciations late Wednesday in Congress, calling the movie ''scurrilous'' and ''blasphemous.''

And in today's editions of The New York Times, a full-page ad for the American Society for the Defense of Tradition, Family and Property carries an open letter to Universal with the headline, ''On the Verge of a Public BLASPHEMY 3/8''

In Pine Bluff, Ark., notes sent to the Flick Twin Cinema and a local newspaper claimed an Aug. 1 fire that damaged the Flick theater was set as a warning not to show or advertise the film.

Both notes, which were turned over to police, were similar and signed in block letters, ''The Lord's Servant.''