Mayor Marion Barry, who still has not committed himself to giving District government employes any pay increase when federal workers receive theirs in October, is planning to withhold all increases next year, too.

His proposed budget for the 1982 fiscal year, which he will submit to the City Council in three weeks, contains no money for salary increases. If approved, that could mean two consecutive years without pay raises for the city's 31,000 workers.

The 1981 budget, which is still before Congress, calls for a modest 5 percent increase, far less than the rate of inflation. But because tax revenues are now expected to be less than was anticipated when that budget was prepared, it is not certain the funds will actually be available.

Even if the 5 percent increase is made available, it is not likely to satisfy District employes, because President Carter has recommended that federal white-collar workers receive an increase of 9.1 percent.

In the past, District workers have generally received what their federal counterparts received. Some workers' organizations have already adopted resolutions calling for city workers to receive the 9.1 percent raise for the fiscal year starting Oct. 1.

Barry appears to be heading for a confrontation with the unions that represent the District's employes, which this year for the first time have a legal right to bargain collectively over wages.

Larry Melton, vice president of the District chapter of the International Brotherhood of Police Officers, said that "if Barry thinks the city employes are going to sit idly by while the federals get 9.1 percent, and then take nothing again in 1982, then he's a one-term mayor. I hope this is a negotiating tactic, but if not he's got serious problems. He's already turned most of the unions against him and destroyed what little morale there was."

Geraldine Boykin, chairman of District Council 20, American Federation of State, County and Municipal Employes, which represents 16,000 workers, stressed that "we have the right to collective bargaining and we are going to present our own proposals. We hope the city will respond to them; if not we'll see what will happen. Our people are already in a very precarious position."

Barry's plan to withhold cost-of-living increases in 1982 came to light yesterday at a District Building meeting of his Citizens' Budget Advisory and special-issue groups whom Barry consults about public opinion on budget matters. The press was excluded from the meeting, but not before Budget Director Gladys Mack had displayed a few preliminary charts revealing some details of the 1982 budget.

Barry had committed himself to balancing that budget without further tax increases. Mack said there was therefore a gap of $158.8 million between how much revenue the city expects to receive and how much it would cost to continue operating the government at present levels of staff, services and salaries -- a gap that will have to be closed mostly by reductions in payrolls. Withholding salary increases, she said, would save $59 million.

She said the number of full-time workers on the payroll, which was 31,326 last June, would be down to 29,354 by Sept. 30, 1981, the end of the 1981 fiscal year, and to "slightly over 28,000" by the end of fiscal 1982. Most of the staff reductions in 1982, she said, would be achieved by attrition, rather than by further layoffs.

City administrator Elijah Rogers, sporting a baby-blue golfing outfit complete with terrycloth visor that matched the mayor's blue open-necked sport shirt, said the choice was between laying off more workers to give salary increases for those who stay on the payroll or cutting out the salary increases to save more jobs.

"We can only spend what we have," he said. "Spending more than we have is what put us $215 million in the hole," a reference to the city's cumulative cash deficit from prior years.

But the immediate issue facing city workers is what will happen on Oct. 1, when federal employes will get either the 9.1 percent increase proposed by Carter or more than 13 percent if Congress fails to approve the president's plan. Union officials said that prices throughout the area will go up as soon as those wages rise, tightening the inflationary vise on their members.

Donald Weinberg, the city's labor negotiator, said the city government's position is that no wage increases for 1981 can be approved "at this time," but he said that "the city is prepared to enter into bargaining."

The upcoming negotiations between the city and the unions will be the first under the District's new personnel law, and complex legal issues have to be resolved before any final decisions are made on what the workers will actually get.

The law requires that bargaining agents for the workers be certified by a new Public Employees Relations Board, headed by former secretary of labor W. Willard Wirtz, before the District can negotiate with them. No such certifications have been issued. Weinberg said no formal negotiations could take place until units are certified.

"That's not our problem," Boykin said. "Our people can't be made to suffer for the lack of a bargaining mechanism. We don't manage the city government. We have a right to collective bargain."

Once the negotiations do begin, the unions are likely to challenge the provisions of the law that severed city workers from salary comparability with federal employes. If the unions lose that argument, city officials consider it probable the unions will go to court.

Barry reiterated yesterday his commitment to keep the budget balanced and to divert some tax revenues to pay off the deficit from the past.

What will happen if the unions hold out for increases beyond those in the budget remains to be seen, but the mayor could be forced to retreat from his pledge to hold the line on taxes.