FBI Director William H. Webster announced yesterday that two FBI supervisors will be fired, another demoted and one suspended because of their roles in illegal surveillance of the radical Weather Underground in the early 1970s.

No administrative action will be taken against 58 street agents involved in the breakins, wiretaps and mail openings, because they were following orders from higher authorities, Webster said.

But he did censure two street agents who entered persons' homes without such approval from superiors, he said.

Though Webster declined to identify those disciplined, sources said one of the supervisors facing dismissal is Horace Beckwith, who once headed the squad in New York City leading the search for the radical fugitives.

Beckwith is alleged to have approved breakins without approval from headquarters and to have ignored instructions while authorizing electronic surveillances and mail openings.

Beckwith's attorney, Brian P. Gettings, issued a statement last night saying he hadn't seen the specific charges but his inclination was that "we will fight anything more than a letter of censure to the bitter end."

It was learned that the other headquarters official being dismissed is Brian Murphy. He didn't stop unauthorized activities and gave investigators answers "unworthy of belief," Webster said.

Another supervisor -- identified as Charles Lunsford, the assistant special agent in charge of the bureau's Washington field office -- will be demoted because he gave "evasive and inconsistent" answers to investigators.

The final supervisor was censured and suspended for 30 days for installing a listening device without specific approval. At the time, the agent -- Gerard Hogan, now special agent in charge of the Milwaukee office, it was learned -- was stationed in upstate New York.

Those facing discipline can appeal. None could be reached for comment.

Webster's action yesterday was spelled out in a 21-page letter to Attorney General Griffin B. Bell and at a morning press conference. The director has told associates he considered the task the most difficult he has faced in his short tenure as head of the FBI.

He said the morale of his 8,000 special agents was not considered in reaching his decision not to punish most street agents. "If I had been a judge outside the bureau, I would have reached the same result," he said.

The investigations of the break-in cases have been especially difficult for the bureau rank-and-file. Many have said they feel the allegedly illegal surveillance of the Weather Underground was warranted by the fugitives' violent behavior.

Former acting director L. Patrick Gray III and two former top aides have been indicted by a federal grand jury for approving breakins of the homes of friends and relatives of the group. Trials are scheduled next month. At the time of the indictments last April, hundreds of FBI agents conducted a silent vigil of support in Washington.

Webster said yesterday that he took the mood of the early 1970s into account in reaching his decision. "There was enormous interest in identifying the Weather Underground," he said.

The group took credit for a series of bombings, including ones at the Capitol and the Pentagon. Several of its leaders went underground in 1969 and pressure was intense on the FBI from the Nixon White House to apprehend the fugitives.

Ironically, there is no evidence that any of the allegedly illegal surveillance techniques used against friends and relatives of the suspects ever resulted in an arrest. Webster noted yesterday that five suspected members of the Weather Underground were arrested a year ago -- by FBI agents who went underground themselves and infiltrated the group.

Eight or nine members of the Weatherman organization are still fugitives and are "the closest thing we have in the United States to international terrorism," Webster said.

The FBI investigation of the group is continuing, he said.

Also, the FBI's internal investigative arm is continuing to explore why congressional committees and the General Accounting Office were given incorrect information about the extent of the break-ins.

This possible cover-up inquiry will continue for another two or three months and will include interviews of some 40 FBI officials, Webster said. Associate Director James B. Adams told The Washington Post last spring that he expects to be questioned because he was in the chain of command approving what was forwarded to Congress. Adams said he didn't know that the information was wrong.

In his letter to Bell, Webster criticized the Justice Department for promising immunity to FBI agents who cooperated in the earlier criminal investigation. Many of the agents have since claimed that they were told they were immune from administrative sanctions as well.

The conflict raises serious questions of fairness, the director said, but they did not hamper his final decision.

Webster also criticized both Justice and his predecessors in the FBI hierarchy for "inexplicable failure" to provide legal guidance to field agents after a 1972 Supreme Court decision banned warrantless wiretaps of domestic groups.

It wasn't until 1976 that formal guidelines for electronic surveillance were issued, he noted. Since then no FBI agent has faced civil liability for such acts.

"Thus it seems clear to me that to discipline street agents at this late date for acts performed under supervision and without needed legal guidance... would lack any therapeutic value either as a personal deterrent or as an example to others," Webster said. "It would be counter-productive and unfair."

Attaching a copy of the guidelines to prevent recurrences, Webster added: "The lessons have been learned."

In a reply to Webster issued later, Bell said he recognized the difficulty the director faced because he had been troubled himself by the criminal investigation. "I know too the strain the inquiry has put on the bueau as an institution," Bell declared.