No one filed yesterday to oppose Alexandria Mayor Charles E. Beatley, a Democrat, in his bid for a sixth term, but Republicans say they may yet offer a candidate.

Although yesterday was the filing deadline for mayor and City Council seats in the city, Virginia elections law allows the GOP to nominate a candidate as late as the party's scheduled March 5 council primary.

Beatley said he would have mixed feelings about running without Republican opposition for the $12,500-a-year job. "It would make it a little easier for me, but it doesn't help the rest of my fellow Democrats," the mayor said.

Beatley said he believes a contested mayoral race would bring out more Democrats in the May 7 city elections and perhaps help the party win more than the four seats it holds on the City Council, which consists of six council members and the mayor.

Republican council member Carlyle C. Ring, who hinted this week that he might challenge Beatley for the mayor's job, tentatively backed down from the race yesterday and filed for reelection to the council. But Ring said his candidacy for the top position remains "an option."

The mayor and the three incumbent Democratic council members kicked off a joint reelection campaign last month.

Council members Patricia S. Ticer, Donald C. Casey and Lionel R. Hope have said the united effort would save money and unnecessary squabbling should there be a need for a Democratic primary. But because only three other Democrats filed for the six council seats, there will be no Democratic primary.

Democrats who filed for the seats yesterday were former Alexandria vice mayor James P. Moran, who resigned in June after pleading no contest to a conflict-of-interest charge; Craig Coverdale, a former congressional candidate, and former council aide Del Pepper.

In addition to Ring, Republicans filing for election to the council included incumbents Robert L. Calhoun and Margaret B. Inman, along with William (Bill) Cleveland, J. Harvey Harrison, Gus S. Lamonde and John Williams. Harrison is a former School Board member.