D. C. Mayor Marion Barry and his top legal aides are lobbying key Republican senators to get them to urge the Senate, which has already refused to act on 17 lameduck U.S. judicial appointees, to approve the nominations of two D.C. Superior Court judges as a gesture of supprot for home rule.

In the wake of Ronald Reagan's presidential victory and the Republican takeover of the Senate in the next session of Congress, GOP senators are awaiting word from the president elect's advisers on whether to proceed on the two local judicial nominees, the only state-level judgeships filled by the president.

Reagan, who before his election was opposed to most of the major home rule initiatives but took no position on the issue of local appointment of judges, has apparently yet gotten around to addressing the confirmation of Ricardo M. Urbina, a Howard University law professor who would be the first Hispanic named to the city's trial court, and Dorothy Sellers, a private Washington lawyer.

Herbert O. Reid, the mayor's top legal counsel, said Friday that he hopes that instead of blocking the Urbina-Sellers nominations, Reagan will use the occasion to send an olive branch to a skeptical city.

"Local people may believe that Republicans in Congress are consciously holding these nominations up," Reid said, "I don't think that's true. I don't think they have thought about them yet. Approving the nominations would be a gesture of support for home rule, and the merit selection of judges" by the city's judicial nomination commission.

Because of the heavy backlog of court cases here, the qualifications of Urbina and Sellers, and because they see the issue as a test of the District of Columbia's home rule powers, city officials and court personnel have trooped up to Capitol Hill or telephoned and written letters on behalf of the two nominees.

"I personally have never seen so much lobbying," said one congressional aide. "The strategy [has been] that it's a very local matter, that the courts should not go any longer without these judgeships filled, and that the [D.C. Superior] Court is the equivalent of a state court, something Reagan should not be very worried about."

Urbina and Sellers also have the support of some prominent local Republicans, including Councilman Rev. Jerry A. Moore Jr. (R-At-Large) and the Republican Chief Judge of the D.C. Court of Appeals, Theodore R. Newman Jr., according to congressional sources.

The two would-be judges themselves have made personal visits to key Senate leaders, trying to distinguish their appointments from the more political federal judgeships and stressing that their confirmations should be viewed as purely local appointments.

But what they are up against, said a Republican congressional source, is that "these are Carter appointments. We are not anxious to see them get confirmed and would prefer to hold back until January."

Local proponents of home rule who believe the judgeships should not fall victim to partisan politics see the issue as unfortunately caught up on the political preregatives of a new administration. If the nominations are blocked or fall through the cracks, they will expire when Congress adjourns in several weeks.

As of late Friday, Urbina and Sellers had no definitive word on whether Reagan wanted the opportunity to reconsider their nominations. The D.C. Superior and Appeals Court nominees are picked from a list of recommendations prepared by the locally constituted D.C. Judicial Nomination Commission.

"At this point," said one congressional source, "the only way we will get these nominations through is if Reagan's people call and say 'Let these judges go.'"

A spokesman for the Reagan transistion team on legal issues said the issue of the D. c. judgeships "hasn't come up in any way, shape or form."

Urbina and Sellers were nominated to the Senate on Sept. 17 by Carter from a list of six names recommended by the Judicial Nomination Commission.

Urbina, 34, formerly was an attorney with the city's Public Defender Service, and was the 1979 Howard Unversity Law School "Professor of the Year." He runs the successful Howard Law School Criminal Justice Program in which students litigate criminal misdemeanor cases in D. C. Superior Court.

Sellers, 37, a partner in the D.C. law firm of Melrod, Redman and Gartlan, specializes in commercial litigation and also has worked on cases concerning women's legal issues.

According to a senior mayoral aide, Barry and Reagan did not discuss the two judgeships at a recent dinner party, but the mayor apparently came away feeling that the new administration would be somewhat responsive to local issues. The Urbina-Sellers nominations may be the first test of that.

"This should be viewed as a home rule issue," said one Senate aide who has been working to help push through the nominations. "These two nominations resulted from a merit selection process [which] Congress established. The local bar has spoken. The president has spoken. It is not a question of quality or integrity, it's just a question of looking forward to a Republican White House."

If Congress adjourns and the Urbina-Sellers nominations expire, officials of the nomination commission said they believe that both names would revert back to the White House where Reagan could either resubmit them or select other names from the original group of six the commission recommended to Carter. That process would delay filling the two court vacancies until sometime next year.