The involvement of three city regulatory board members in a bid to redevelop a key parcel of city-owned land raises "serious questions of propriety," a D.C. City Council member charged yesterday.

The three, who joined the Western Development Corp. in submitting a proposal last Friday to rebuild a tract of land at the Gallery Place Metro stop, have placed "themselves in the possible position of achieving personal financial gain through association with" a developer, charged Polly Shackleton (D-Ward 3).

For members of the city zoning boards to have such a relationship with a developer "seems to me inappropriate," she said. "Millions of dollars ride on some decisions of the two (zoning) bodies."

She identified the three, who serve as $100-a-day part-timers, as Ruby B. McZier, chairman of the city Zoning Commission; Leonard L. McCants, chairman of the Board of Zoning Adjustment, and Larry C. Williams Sr., a member of the city Alcoholic Beverage Control Board.

McCants and Williams both strongly denied any possibility of conflict yesterday and said they had offered their resignations to Mayor Marion Barry if any arose. McZier, out of the city because of a family illness, could not be reached.

All three individuals are lawyers. McCants and McZier are appointees of former mayor Walter E. Washington, and have terms running until 1980 and 1982, respectively. Williams was appointed by Barry for a term that runs until 1981.

The Western Development bid was one of five submitted for the site, where the city hopes to erect a $100-million-plus hotel, retail and office project. The land agency expects to make its decision on the tract, bounded by F, G, Sixth and Seventh streets NW, in November.

One of the other bids was submitted by Gallery Center Corp. in association with James L. Denson, part-time chairman of the D.C. Board of Elections and Ethics. Although Denson might have to sit in judgment of any charge of conflict in the case, Shackleton did not raise any issue in his case. She said Denson's duties are remote from land development and licensing policies.

Denson was appointed to the elections board by Washington and named as its chairman by Barry.

McCants said he was advised by Louis P. Robbins, the former acting corporation counsel, that there was no conflict in his joining in the bid. "Out of an abundance of caution, I wrote a letter to the mayor (Barry) advising him," McCants said.

Williams said all three had indicated clearly to the redevelopment agency that they had city posts, hoping to neutralize any impression that they were trying to use influence. "I think I can speak for the three of us: we have no intention of muddying our professional careers," Williams said.

Shackleton said the two zoning bodies often serve as planning agencies in dealing with contested cases between citizens and developers.Moreover, she said, a policy issue on the location of hotels in residentially zoned areas of the city is pending before the Zoning Commission. A 250-room hotel has been proposed by Western Development as part of the Gallery Place project.