The former Washington law firm of Patricia Roberts Harris, the administration's chief advocate for urban America, has recently gone into the business of representing cities.

Two lawyers in the firm of Fried, Frank, Harris, Shriver and Kampelman said yesterday their organization now has "a handful" of cities as clients and is seeking more. The clients include Atlantic City and El Paso.

The lawyers, who asked not to be named, said, however, that the firm has had "zero" contact with Harris, who had been a partner there from February 1970 until she resigned when she became secretary of housing and urban development a year ago January.

Harris said the firm's efforts to represent cities "comes as a surprise to me. I have had no association with that firm since I resigned." A HUD spokesman added, "The fact that she was once a member buys them nothing now."

Richard Cherry, director of the National Center for Municipal Development, a nonproof corporation that represents 46 cities, said he was concerned about the firm's urban activity because of its past ties with the HUD secretary.

"They may not be doing this explicitly, but obviously they're trying to sell their connections with Pat Harris - I assume that's what they're doing," Cherry said.

"If cities have a bigger name firm representing them, they're going to be more competitive with our cities. I would think they would have an implicit advantage because of Harris."

The center was set up by the National League of Cities and the U.S. Conference of Mayors to help cities get federal grants and, said Cherry, to serve as "an early warning system to alert cities not just to what the feds are going to do for them but to them, such as imposing new environmental rules, fair labor standards or Social Security regulations."

One lawyer at Fried, Frank stressed that the firm is talking to officials from other cities about representing them, "but it's at their initiative, not ours."

"We haven't actively pursued this," he added. "We have turned down some city clients because we felt they were just after our old association" with Harris.

The firm has been involved for years in housing and community development and has represented public "entities" such as nonprofit community groups, colleges and Indian tribes, he said.

"Atlantic City is involved in a hugh redevelopment effort in addition to its casino development," he said. "We have been asked to help it implement the plan, which includes a $150 million convention center contiguous to some of the casino resorts. We're helping set up the financing. There's a lot of housing development and we're trying to get aid from HUD and from private sources."

Dan M. Ponder, mayor pro tem of Fl Paso, said his city contacted the Fried, Frank firm last May because a local developer, Al Lemley, had suggested they use his lawyer, Richard Schifter, who is a partner in the firm.

"When we came to Washington in May, Schifter told us Harris had been in the firm and had left to go to HUD and that he might not be able to help us much at HUD because he wouldn't want to create any conflict of interest," Ponder said.

"We work with a young man in the firm named Leonard Zax, who knows HUD because he worked there under the two previous secretaries. He helped us apply for a $300,000 grant which would be seed money to help us redevelop part of our downtown."

Ponder said the city has also hired another Washington law firm - Akin, Gump, Rauer and Feld - which used to be firm of special trade negotiator Robert S. Strauss. "They're trying to get us an urban development action grant from HUD, but I don't have any way of knowing if the old Strauss connection will help" Ponder said.

The Akin, Grump firm used to have the name Strauss in the middle. The Fried, Frank firm still has the name Harris in the middle.

"But it never referred to Pat Harris," said one of the firm's lawyers. "It refers to Sam Harris, who's in our New York office and who has been with the firm for years. In this town, there's an overemphasis on connections, and when we tell people about Sam Harris, they smile and say, 'Oh, sure.'"