The U.S. Court of Appeals here yesterday ruled that the public affairs director of the Church of Scientolgy cannot refuse to testify before a U.S. grand jury investigating the sect's alleged illegal activities merely because he also is a minister in the church.

The minister-publicist had invoked a general First Amendment privilege based on religion in refusing to answer questions in his appearace before the federal panel lst July 29. He was ordered to jail for contempt of court by U.S. District Chief Judge William B. Bryant.

Arthur J. Maren, who has spent the last 35 days in D.C. jail, attempted to win his release yesterday about three hours after the appellate court ruling by saying that he would no longer invoke a First Amendment claim now that it has been rejected at the appellate level.

However, acting Chief U.S. Judge John H. Pratt refused to release Maren after the minister-publicist said under oath that he probably would still refuse to testify before the grand jury when it met against next week - this time invoking Fifth Amendment right against self-incrimination.

Pratt said he took Maren's testimony as an indication that he would continue to "stonewall it" before the panel. The grand jury is investigating allegations that the church's hierarchy directed a massive plot to infiltrate government agencies, steal government documents and "bug" at least one government meeting.

Pratt quoted the appeals court opinion that pointed out Maren had not previously raised his Fifth Amendment privilege and said the minister appeared to "disdain that privilege as a defense."

Maren, who is based in Los Angeles, was one of the first Scientologists to be subpoenaed before the grand jury after the government conducted searches at the sect's Washington and Los Angeles officies.

Maren refused to answer questions about whether he knew a former Scientologist who pleaded guilty to using faked credentials to enter the U.S. courthouse here, and whether he knew about the alleged bugging of an IRS meeting by Scientologists in Los Angeles.

To the questions, Maren replied that he felt the government was attempting to pry into the inner workings of the church and that he should not have been called as a witness.

The appeals court ruling yesterday said there was no blanket provision that would block Maren from being called before the panel and being interrogated.

"Assuming arguendo that Scientology is a religion within the meaning of the First Amendment and that appellant is a minister, we must deny appellant's sweeping assertion that solely by virture of his status as a minister of the church he may refuse all questioning . . ." the appeals court ruled.

The court did point out that Maren could "seek court protection from official harassment" if there is any indication that he is being asked irrelevant questions before the grand jury.

"In any event, appellant has been fully informed of the grand jury's mission and the relevance of the questions to the grand jury's investigation is undisputed and indisputable," the court added.

Upholding the contempt citation against Maren in an unsigned opinion were U.S. Circuit Judges Roger Robb, Malcolm R. Wilkey and Spottswood Robinson III. Robinson issued a separate additional opinion indicating he felt that Maren could raise a First Amendement claim if certain questions were asked about his beliefs.

After Pratt refused to release Maren yesterday afternoon, a spokesman for the Scientology Church called the ruling "a dark day for justice in America."

The spokesman said the hearing before Pratt was an "obscene mockery of the democratic process" and that the government's only reason for keeping Maren jailed "is to apply legal thumbscrews and punish this heroic minister for his beliefs."

The Scientologists, who have formed a group to fight against what it contends is grand jury abuse, said it is launching an investigation into the Justice Department's handling of the grand jury system.