Employes of the D.C. government and public schools are beginning their first round of wage negotiations armed with evidence that their salaries are lower than those of their counterparts in the federal government and in some other major cities, and in many cases lower than those of workers in the Washington suburbs.

Wage comparison studies conducted by city workers' unions and by the District government in preparation for negotiations over wages and working conditions this year show that while District salaries generally are competitive with those in other jurisdictions, they seldom are at the top.

Workers in Montgomery County are usually paid more, and those in Prince George's County usually receive less. Prince George's salaries for most public jobs are the lowest of the adjacent suburbs.

A social worker, for example, can make up to $29,133 a year working for Montgomery County and $25,412 in Fairfax County, but only $23,252 in the District and $16,281 in Prince George's. A registered nurse can earn up to $25,302 in Montgomery, $21,459 in Arlington, $20,953 in the District, and $18,325 in Prince George's.

Nationally, the studies show, city workers' salaries are generally highest in Detroit, which has economic problems far more severe than those confronting Mayor Marion Barry's cash-strapped administration here.

A Detroit patrolman can earn $26,296 after only four years on the force; the District maximum is $23,553 after 16 years. In Prince George's, the top is $17,555 after six years.

Confronted by contracts requiring such high wages, Detroit Mayor Coleman Young has resorted to massive layoffs, cutting workers off the payroll to meet the salary requriements of those who remain.

Barry, facing a reelection campaign next year in a city where many blacks view the city payroll as a source of economic stability and prosperity, has said that he hopes to avoid a similar course of action.

Washington's mayor has laid off more than 1,000 workers in the past year. Barry argues that employes should be restrained in the forthcoming contract negotiations so as to save as many jobs as possible; the more costly the wage settlements, the fewer people the city can afford to keep on the payroll.

The pay comparison studies show that municipal workers in Washington are much better paid than those in such traditionaly low-wage cities as New Orleans and Buffalo, but in many categories they lag behind other major cities, even some where the cost of living is less.

Among all workers and teachers in all cities of more than 400,000 population, the only job in which District employes are at the top of the pay scale is that of social worker.

The maximum annual base salary for a District government social worker, $28,134, is higher than in any other large city, but still slightly lower than the $29,236 a social worker on the federal payroll can earn and less than the $29,133 maximum in Montgomery County.

D.C. government workers ar paid less than their federal counterparts across the board because this year, for the first time, they lost the salary parity they had when the city's personnel system was effectively a part of the federal civil service system.

Barry gave city employes an increase of 5 percent over last year's wages while former president Jimmy Carter was giving federal workers an increase of 9.1 percent.

This year's general raise also may mark the last time all D.C. government workers receive the same salary adjustment. Henceforth, under the terms of the D.C. Merit Personnel Act, the employes must negotiate their wages and different groups of workers probably will receive different settlements.

Negotiations for three-year contracts that will take effect Oct. 1 are in their preliminary phases. When completed, they will determine the wages and other compensation for all the different groups of workers included in the overall payroll of about 30,000. Among them are clerks and sanitation collectors, nurses and mechanics, teachers and computer programmers, librarians and jail guards.

Barry's budget for the fiscal year that starts Oct. 1 contains only enough money to fund an increase of about 2 percent. He already has said he recognizes that much more will be required, though it is not clear where the additional money would come from.

The wage-comparison studies were completed in early May and thus do not reflect salary adjustments approved by local governments since then. The city Alexandria, for example, recently granted its workers an increase of 9.5 percent for the coming year.

The data reports differences in overtime pay and in length of work week, but it does not reflect differences in pension benefits, sick leave or vacation policy.

The studies show that the maximum annual base salary of a D.C. police patrolman, $23,553, is the highest in the six area jurisdictions analyzed. Fairfax is second at $23,185, followed in order by Montgomery County, Arlington and Alexandria, with Prince George's trailing at $17,555.

The comparable figure for Detroit, highest among the 40 largest U.S. cities, is $26,296. For Buffalo, lowest of the 40 cities, it is $16,252. The figures for firefighters are similar.

For another group of workers, clerk-typists, the District is further from the top. The annual maximum in the District, $13,713, trails Montgomery's $15,298, and also trails Arlington and Fairfax. Prince George's and Alexandria pay less. Nationally, Detroit is far ahead, with an annual maximum over $17,000, and Kansas City is lowest at $10,812.

An auto mechanic can make $25,012 working for the city of Houston, but only $21,622 working for the District. The hourly wage for an auto mechanic in the District, $10.91, trails Montgomery's $11.08, but leads Fairfax, Arlington and Alexandria. Prince George's trails at $7.79.

The maximum annual base salary for a classroom teacher in the District, $26,472, is fourth among the six area jurisdictions studied. Alexandria is by far the highest at $37,658, followed by Fairfax and Arlington. Prince George's and Montgomery trail the District in this category. Among the 40 largest cities, Philadelphia's $31,080 is the highest and New Orleans' $20,339 is the lowest.