D.C. Mayor Marion Barry, facing renewed speculation about his future amid indications that his political support has eroded, said yesterday that he does not expect to be charged in the federal probes of his administration and that he would not resign from office even if he were indicted.

"The only way I would get out of this office is to be carried out of here," said Barry, who has more than three years left in his third term of office.

Barry made the unusually strong comments two days after publication of a Washington Post poll showing that the continuing federal investigations have cost Barry political support in the city and increased skepticism about his personal integrity.

The comments also came in the wake of a report in The Washington Times yesterday that said some of the mayor's closest advisers have urged him to consider resigning. Barry's advisers sharply disputed the story, but their comments did little to restrain widespread circulation of the account on radio and television.

Knowledgeable aides said Barry would be unlikely to resign for several reasons. "His tenacity is being grossly underestimated," said one official familiar with Barry's strategy sessions.

A resignation for any reason would be seen as an admission of wrongdoing that would ruin any chance of Barry's clearing his name, aides said. They added that it is unlikely that U.S. Attorney Joseph E. diGenova, who is leading the probes, would end any investigation of Barry simply because the mayor resigned.

A resignation also could curb Barry's power to defend himself, aides said. By leaving office, the mayor would relinquish a platform that is useful in shaping public opinion, they said. He also would be unable to command the political support that he has now as the chief executive of city government and would be out of a job at a time when he was facing potentially large legal fees. Barry is represented now by his legal counsel, Herbert O. Reid Sr., who is paid by the city.

In responding to the probes, Barry has adopted a posture that is alternately combative and contemptuous, characterizing the situation as "war" and then mounting a public effort to belittle the inquiry as a "Mickey Mouse" operation.

The mayor said yesterday that he believes the prosecutors are pressing ahead because they "have gotten way out there" in an attempt to weave a conspiracy out of what Barry said were normal social and business connections between city officials and private D.C. government contractors.

Federal investigators are probing allegations of contracting abuses, spending improprieties and obstructions of justice by city officials and others.

Barry said that he was "elated" with the results of the Post poll, despite the drop in his job rating from 50 percent recorded in July 1986 to the present 44 percent. The mayor said the poll indicated that his base of support remains solid in the face of intense media attention to the probes.

According to city officials, the mayor would not be required to resign unless he were convicted of a felony.

The Post telephone poll showed that two out of three respondents believe corruption is a major problem in the city government. More than half said the federal investigation is justified.

When asked to rate Barry's personal honesty and ethical standards, 47 percent of the 513 city residents in the survey described them as "not good" or "poor" -- a 9 percentage point increase from the poll 13 months ago.

"The public has been fed a daily barrage of negative stories . . . . I'd believe it, too," Barry said yesterday.

In an example of how the investigations have intruded on the mayor's routine business, Barry yesterday interrupted a lunch with city sanitation workers to call WTOP-AM radio with a request that he be allowed to go "live" on the all-news station. Barry had heard that the station was asking people on the street whether he should resign. Clearing his throat, Barry vigorously rejected the idea on the air and said his government "is running better than ever."

Station officials said Barry has called the station before, but that it was unusual for him to ask to go on the air immediately.

In interviews with reporters yesterday, Barry said that despite the Post poll and continued negative reports about his administration, no one has emerged in the city with the political strength to challenge him seriously in an election.

"There's no need to be egotistical about it," Barry said, "but I can beat anybody in this town."

"He's still a formidable opponent," agreed Joslyn Williams, president of the Washington Labor Council, AFL-CIO. "It is not the nature of the mayor to cut and run. On the contrary, considering his background, he is a street fighter and seems to relish battles."

Greeted warmly at the luncheon held at a Southwest Washington restaurant, Barry told about 40 sanitation workers, "Our administration is under attack now. But that's nothing new . . . . I'm not going to let anybody . . . break my spirit. I'm not going anywhere. My term is three years and some months . . . . We're here to stay."