The 14 unions representing District of Columbia city workers escalated their demands in an opening round of wage negotiations yesterday, asking the city to stop replacing public employes with private contractors.

One union representative, A. J. Ciampa, vice president of the American Federation of State, County and Municipal Employees (AFSCME), said that the unions will insist during the negotiations that the city stop "contracting out" work and that there be an end to layoffs of city workers. He also reiterated the unions' long-stated demand that municipal workers be given a 9.1 percent pay increase, retroactive to Oct. 1 when the current fiscal year began.

Mayor Marion Barry's tenuously balanced budget calls for only a 5 percent cost-of-living increase, and the city's official position is that it cannot afford to pay any more than that.

The unions' increased demands apparently are designed to provide additional bargaining chips during the negotiations that began yesterday afternoon with a closed-door budget briefing by Barry, his budget director Gladys Mack, City Administrator Elijah B. Rogers and other Barry aides.

City officials are not referring to the current round of talks as "negotiations," since Barry has taken the position that collective bargaining this year would be illegal while there is technically no bargaining mechanism in place. The city's Public Employee relations Board (PERB) has ordered the city to begin collective bargaining immediately with the unions, but Barry challenged that order as invalid in a suit in D. C. Superior Court.

For the city now to say publicly that these talks are in fact negotiations would preempt the city of its official position. PERB's director, former U.S. Secretary of Labor Willard Wirtz, who is mediating the talks, said at the end of yesterday's initial meeting, "We're not going to get hung up on one [word]."

But the unions are clearly taking the position that the discussions that began yesterday are the collective bargaining talks they have been demanding. "We call them negotiations," said one union official who asked not to be named. "A rose is a rose is a rose, no matter what you call it."

Wirtz said the session yesterday, at the Martin Luther King Library, was "a very, very constructive discussion. There was a broader basis of understanding of the situation." Wirtz said the two sides would continue talking and that the PERB's role was informal, not that of an official mediator or arbitrator.

Once an initial budget briefing was completed after 90 minutes yesterday, Donald Weinberg, the city's labor negotiator, and five representatives of city unions, stayed behind for another half hour, to work out the ground rules for the rest of the talks, according to one source.

Both sides have agreed not to comment publicly on the status of negotiations.