An association of Washington Realtors has mounted an independent $16,000 advertising campaign on behalf of mayoral candidate John Ray, who has been criticized by his rivals for accepting too many campaign contributions from real estate interests.

The advertisements, which tout Ray as a "role model for our youth," began appearing this week on the backs and interiors of several hundred Metro buses, said Donald R. Slatton, executive vice president of the Washington D.C. Association of Realtors. The ad campaign will coincide with the final full month of the Democratic mayoral primary.

"D.C. really needs a person of John's stature," said Slatton, whose group also contributed $2,000 to Ray's campaign directly. He said Ray would be a "mayor who will bring the integrity, the credibility and the political experience to help the whole city grow."

Ray, stung by recent criticism of his acceptance of large amounts of campaign funds from developers, began a counteroffensive yesterday, calling a news conference to denounce the "harsh personal attacks" of two Democratic rivals, D.C. Delegate Walter E. Fauntroy and D.C. Council member Charlene Drew Jarvis (Ward 4).

Ray, an at-large member of the D.C. Council, singled out Fauntroy's comment this week that Ray, who is black, is the "great white hope" of outside developers, saying it was a "term that could divide the city" along racial lines.

Fauntroy's remarks were "unbecoming of a reverend," Ray said. "Certainly we expect more, much more, from someone who has been in Congress for 19 years, who is the pastor of a large church and who is part of the Christian community."

Ray also said Jarvis made an "unnecessary" personal attack this week when she said that D.C. Council Chairman David A. Clarke was "temperamentally unsuited" to be mayor.

A Jarvis spokeswoman said Jarvis had simply "reiterated what Clarke himself has admitted -- that his temper is an issue he must address."

Robert L. Johnson, Fauntroy's campaign manager, said Fauntroy "stands by his statement that John Ray has been annointed as the great white hope of outside developers and others who are opposed to the interests of African American people of Washington."

Ray also called on the D.C. Office of Campaign Finance to require Fauntroy to make a full disclosure of the types of businesses contributing to his campaign. Unlike Ray, Fauntroy has not identified the types of businesses being operated by corporations that contributed to his campaign, as Ray says is required by the law.

Marianne Coleman Niles, director of the Campaign Finance Office, said her agency is considering Ray's request and declined to comment.

Both Ray and Slatton said Ray's campaign provided no encouragement or assistance to the Realtors association as it mounted the ad campaign. Such independent expenditures are permitted under D.C. law, as long as there is no cooperation between the group and the campaign.

Ray and his campaign press secretary, Margaret Gentry, said they were notified recently about the campaign by the Realtors' political action committee, but Ray said, "They're totally on their own, independent of us."

Ray acknowledged that the ad campaign might provide fresh ammunition to his critics, but he sought to distinguish between the Realtors and developers. "You're talking about people who sell houses," he said. "But I'm sure that Fauntroy's campaign, the way they are going, will try to make them developers."

On a separate front, Ray was forced to defend his allegations this week that the city is wasting millions of dollars in payments to contractors to repair the District's streets.

"I can tell you we are spending millions and millions of dollars here we shouldn't be spending," Ray said in an interview Monday with The Post. He added, "We don't have anyone really auditing money from these road construction projects."

Ray also said people "on the inside" of the construction business have told him that contractors often reap profits in excess of 100 percent on street resurfacing jobs.

"It was kind of a surprise to me," said Arthur J. Hill, the Federal Highway Administration's director for the District. "Contractors are allowed to get some profit, but we don't know anything about any 100 percent."

After talking with Hill on Tuesday, District Public Works Director John E. Touchstone called Ray and told him that District officials are not aware of any impropriety. "We just have no idea what he's referring to," said department spokeswoman Tara Hamilton.

In the interview with The Post, Ray cited K Street NW and 14th Street NW as examples of projects in which contractors allegedly were paid too much. The city recently spent $6 million rebuilding K Street between 16th Street and 21st Street, but officials said there have been no major resurfacing projects on 14th Street for several years.

Ray yesterday stuck by the allegations, although he backed off including 14th Street in his criticism. Ray attributed the allegations to a contractor who approached him at a candidates' forum in Ward 3.