The entry of D.C. Council member Carol Schwartz (R-At Large) into the race for mayor is likely to stimulate a wide-ranging debate on Mayor Marion Barry's performance and record, and turn a lackluster contest into an intense campaign, city politicians said yesterday.

Schwartz's candidacy is viewed by many as a long shot. But as a citywide officeholder who upset a longtime incumbent backed by the mayor's supporters in the 1984 at-large council race, she is a challenger Barry will not be able to dismiss lightly, they said.

"Carol's candidacy clearly is going to activate the mayor's campaign so that he is going to have to deal more specifically with the issues," said one Barry aide.

Barry, who was hoping this year to exceed the record $1.3 million he raised in 1982, is likely to have an easier time raising funds now that he has a strong challenger, city politicians said.

Schwartz's candidacy also is expected to force the mayor to respond to criticism of his policies in the key areas of city taxes, delivery of services, housing, corrections and city contracting.

Schwartz, 42, a former D.C. school board member who lives in Ward 3, has avoided directly addressing the corruption issue but city politicians said she stands to benefit from any further disclosures of wrongdoing. Within the past year, Barry's former top aide, Ivanhoe Donaldson, began serving a prison sentence on fraud and cover-up charges and a number of other high ranking city officials have been the subject of federal investigations.

In addition, the entry of a well-known Republican promises to alter the pattern of the two previous mayoral campaigns since the beginning of home rule.

Barry, in the 1978 and 1982 primary races, faced strong Democratic opponents, while this year he is up against only token opposition in the Democratic primary and has already raised 100 times more than his opponents. With Schwartz's entry into this year's race, the primary contest may well take a back seat to the Nov. 4 general election.

At a news conference yesterday, Barry brushed aside reporters' questions about Schwartz, calling her a "novice on the council."

"I am not going to spend my time worrying about what she is doing. I am going to spend my time being mayor of this city," he said.

Barry said he would debate Schwartz and any of his other opponents under the right conditions, but "I am not going to give anybody free publicity. I am not going to go out and create a forum. I will debate in a forum that is appropriate."

Announced candidates for the Democratic nomination for mayor include former school board member Mattie Taylor and sex entrepreneur Dennis Sobin. Independents Brian Moore and Calvin Gurley have also announced their candidacies. Alvin C. Frost, a former city finance official, is expected to announce plans to run for the Statehood Party nomination.

Schwartz, in her announcement speech Tuesday, said the Barry administration has proved inefficient in managing city programs and vowed to cut taxes while improving basic city services.

Brian Moore issued a statement yesterday criticizing Schwartz for failing to concentrate on the corruption issue.

"Why is she being so nice to the mayor?" asked Moore, who has made corruption a major part of his campaign. "If Mrs. Schwartz doesn't want to get her hands dirty, then why run?

Schwartz, asked about the corruption issue yesterday, said, "I want to run a positive campaign. I am going to hammer at city mismanagement and the problems of our city. And, of course, that corruption is one part of it. If you are properly managing the city you don't have these types of problems."

Since Donaldson's conviction in December, some city politicans have suggested that further embarrassments might emerge from continuing investigations of city government. But until Schwartz's entry, many observers doubted that any challenger could capitalize on what some may feel is a corruption issue.

"Everybody on the street is saying that something is going to happen this summer," said one council aide. "So what? There was noboby to pick up on it. Now there is. She could be a real dark horse."

Schwartz can be expected to do well in her home base of Ward 3, the predominantly white and affluent northwestern section of the city, which she represented for eight years on the D.C. school board. The ward, the only one of the city's eight wards that did not support Barry in the 1982 Democratic primary, has been the center of anti-Barry sentiment in the city.

"I think Carol will get a big protest vote -- not so much for her but against the mayor," said one Ward 3 politician.

City politicians said they are skeptical that Schwartz can cut significantly into Barry's strength among city blacks, who make up 70 percent of the District's population.

Schwartz, the only Republican on the council, was elected to an at-large seat in 1984 after a bitter primary battle against incumbent Rev. Jerry Moore Jr., who is black. Supporters of Moore said yesterday Schwartz will have to work hard to overcome lingering resentment among some blacks.

However, Marjorie Parker, a prominent Republican black, said she believes Republicans will unite behind Schwartz and that any divisions have already healed.

"There are many people who are Republicans who are glad that she is a candidate because it will impact on the kind of race that the mayor runs," she said.

Schwartz, who has said her decision to run was made at the last minute, said that she will open a temporary campaign headquarters today in the offices of Conrad P. Smith, a former Ward 1 school board member and a longtime Schwartz supporter. Schwartz, who will act as her own campaign manager, said she does not plan to raise funds from the national Republican Party.

"I do not expect any help, nor am I seeking any help," she said. "This is a local race.