The first Church of Scientology minister to undergo extensive questioning by a faderal grand jury probing the church's activities was sent to jail for an indefinite period by a federal judge yesterday after he refused to answer questions before the jury.

U.S. District Chief Judge William B. Bryant took the action after three separate hearings in which the minister, Alfred Maren, of California, had been told by the judge that his reasons for refusing to answer questions before the panel were invalid.

Maren could remain in jail until he decides to answer the question, or until the end of the term of the grand jury that is hearing evidence concerning the scientologists. The grand jury's expiration date is next April.

Maren was first brought before Bryant about 10 a.m. yesterday on a motion by Executive Assistant U.S. Attorney Henry F. Schuelke that the minister be forced to answer questions concerning his knowledge of documents allegedly stolen from the government by a church operative.

Maren had refused to answer those questions in a previous appearance before the grand jury on what several attorneys said were novel grounds. The grounds included his objections to the prosecutors participating in the grand jury sessions, the scope of the questions themselves, and his belief that the government was prohibited from asking such questions because Bryant had invalidated a search warrant executed against the church.

After hearing arguments on those points by Maren's attorney, Daniel Sheehan, Bryant ordered the minister to respond to the questions before the panel unless there was a legally recognizable privilege he intended to invoke.

After Bryant ruled, Sheehan asked the judge if he had "read the briefs" in the case and attempted to continue to argue after the ruling. "I've ruled now," Bryant said, telling Sheehan to stop.

About five hours later, Bryant was call back to his courtroom by prosecutor Schuelke. Schuelke said Maren was invoking the same privileges that had already been rejected by the judge.

Bryant, known for his calm courtroom demeanor, turned [WORD ILLEGIBLE] Sheehan and said, "If you have anything new to say to me, I'll hear it. If not, I don't want to hear it."

He rejected Schuelke's request that Maren be jailed immediately for contempt of court. Bryant then called the minister before him and said, "Bluntly, I'm ordering you to answer the questions." He added that he would have no alternative but to order him jailed if he didn't.

By 5:30 p.m., prosecutors, Sheehan and Maren were back in Bryant's courtroom. This time, Maren wearing black clerical garb, was brought forward. After hearing that Maren had not changed his position, Bryant ordered Maren jailed immediately.

Sheehan again began objecting to the manner in which the prosecutors were conducting the investigation.

Bryant, by this point clearly exasperated, said, "I don't want to hear any more of that. You've advised this witness to refuse to answer questions on invalid grounclear."

A Church of Scientology statement issued after the jailing of Maren called the action "constitutional heresy." It said that although the sect's ministers "have no wish to become martyrs . . . this may be part of the inflated price of freedom in 1977."