Mayor Marion Barry, concerned that he may not be able to keep his top managers, said yesterday that he plans to ask City Council to raise the salaries of high-level District government administrators.

Barry's statement came after City Administrator Elijah B. Rogers, one of the highly-touted managers Barry hired when he took office two years ago, said last week that he will consider leaving the city government if a better-paying job as city manager of Oakland, Calif., is offered to him. Rogers has been mentioned as a candidate for the Oakland job.

Barry said he will propose that he be allowed to set the city administrator's salary. He said he wanted to see other department heads' salaries set according to a three-tiered schedule, with those administrators with the most responsibility being paid more than others.

Currently, Rogers is paid about $53,000 a year. The Oakland job, for example, currently pays $65,000 annually, and Barry said his top aides all generally lag behind their counterparts of other cities.

Salaries of the city's cabinet-level department heads are now limited to a maximum of $50,112 a year. Baryy makesw about $64,000 a year, which, he said, is less than some other mayors.

"Our people are stuck at $50,000," he said. "So what do they do about inflation? They just have to absorb it. I have to absorb it, too."

Barry said he planned to ask the council to set three levels of executive pay. The highest level, he said, would be for officials such as James E. Buford, who heads the massive Department of Human Services, the largest in the city government.

A medium level would be set for more department heads, Barry said, and a lower salary level would be established for officials who have cabinet rank but supervise only a few employes, such as the director of the Rental Accomodations Office.

"We couldn't do this before, either philosophically or politically," Barry said. He explained that with low-level employes being laid off and the public growing increasingly restive about cutbacks in city services, he felt he could not propose a pay increase for high-level aides.

But now, Barry said, the layoffs are essentially over and "the work force is settled down." He declined to say how much he thought the top administrators ought to be paid now.

Barry also said yesterday he intends to begin implementation of the legalized gambling initiative that officially became law last week by sending to the City Council nominations for the five-member gaming board mandated by the measure "within the next 10 to 14 days."

Barry said his nominations, which an aide called "the biggest plum in years," would likely include proponents of the successful initiative.