Religious groups as diverse as Scientologists and the National Council of Churches joined forces in federal court today to oppose a Clearwater, Fla., ordinance that extends charitable fund-raising regulations to churches.

"For the first time in the history of this country, a church must obtain a license to pass the collection plate among its own members on its own premises," attorney Eric M. Lieberman of Miami told the 11th U.S. Circuit Court of Appeals. "Until now, no government entity in this country has dared to assume such sweeping power."

The ordinance, validated last year by a federal judge in Florida, requires any group -- including churches -- with more than 20 members to register with the city before soliciting funds for a tax-exempt purpose and to keep detailed records of receipts and disbursements.

It grew out of 10 years' tension between the city and the Church of Scientology, whose Western Hempisphere headquarters are in Clearwater. But mainstream churches contend that the ordinance's reporting and record-keeping requirements are burdensome and intrusive.

They also object to a provision giving the Clearwater city attorney broad subpoena power for records of charitable and religious organizations. He can investigate a group after receiving 10 complaints.

In an effort to skirt constitutional problems, the city agreed to let churches disclose financial details to their own members instead of to the city, and fund-raising under $10,000 annually does not have to be reported. But the religious groups are far from satisfied.

"We are persuaded to believe this is model legislation and that if it can be implemented in Clearwater, it will be throughout the United States," the Rev. Robert McCurry, a Baptist from East Point, Ga., said in an interview.

McCurry was one of about 100 people who demonstrated outside the federal courthouse before the arguments. The group, all white, sang the theme of the civil rights movement, "We Shall Overcome," and carried signs reading "Civil Rights in the '60s, Religious Freedom in the '80s."

"Passing the collection plate is regulated but not panhandling outside the church," said Lee Boothby, attorney for Americans United For Separation of Church and State. "The Baptist bookstore is covered but not a porn shop down the street . . . a Billy Graham revival but not an Amway convention."

Washington attorney Lawrence Velvel, who is representing Clearwater, said the ordinance was "merely a registration and disclosure law. It doesn't stop any person or group from soliciting funds. It doesn't interfere with anybody practicing religion."

Charitable organizations have coped with similar regulations for years without duress, Velvel said. "This hasn't destroyed charity, which has flourished in this country as nowhere else."

U.S. District Court Judge Elizabeth A. Kovachevich upheld the ordinance last year in Florida without a hearing on its potential impact on church-state separation. Appellate Judge Gerald B. Tjoflat criticized that action, saying it left the appeals court without adequate information on which to decide "this very important case."

Tjoflat suggested that the case be remanded to the trial court. Because the ordinance could extend regulation of religious groups into new legal territory, both sides expect the case to reach the Supreme Court.