Federal employee unions that have been losing money and people in recent years would get a massive permanent and mandatory financial boost from nonmembers under a bill about to emerge from a House civil service subcommittee.

It would require several hundred thousand U.S. workers who don't now belong to unions to pay special fees - of from 10 per cent to 80 per cent of regular union dues - for being represented by the union. The money also would be used for telephone bills, stationary, postage and newsletters of the union as part of its representation of the overall work force.

The fee - or "fair share" - concept already is used by some state and local governments. It would be introduced to Uncle Sam in a labor-management bill being cosponsored by Reps. William Clay (D-Mo.) and William Ford (D-Mich.), two of organized labor's best friends in Congress. Government unions, and the AFL-CIO, have mad the labor-management bill one of their "must-have" items in this congress.

If the Clay-Ford bill becomes law, it would mean that as many as 600,000 government employees who don't belong to unions, for whatever reason, would have to help pay some of the union's expenses if it had "exclusive" bargaining rights in their agency. It would nearly double the income of some unions that have small memberships in agencies where they have exclusive bargaining rights on behalf of a much larger group of workers.

One of the big gainers in the "fairshare" proposal would be the federal establishment's biggest union, the American Federation of Government Employees. The Afl-CIO organization has about 280,000 dues-paying members and, like most other federal unions, is being hit by the financial squeeze. But AFGE has exclusive bargaining rights for 678,410 workers whom it must represent. So, under the fair-share concept, it would charge a representation fee to the nearly 400,000 non-members under its jurisdiction.

Unions argue that the fair-share idea is equitable, since "free riders" (people who don't belong) are happy to accept all the benefits unions win for them, and for which members pay. The fair-share concept is agreeable to most union members since it makes nonmembers contribute to the cause but does not drag the unwilling into membership, the way a union shop does.

Many government workers who do not belong to unions argue that - compared to private-sector groups - federal unions are relatively powerless because they can not strike, and cannot bargain over basics like pay and fringe benefits. The Ford-Clay bill would give unions much more bargaining clout and end, backers believe, the argument that paying union dues in government is a waste of time and money.

Union brass think the labor-management bill has a good chance of becoming law next year. Top federal labor experts (who do not like the idea) do not htink it has a very good chance.

The White House, as it tends to do, says it is for improved labor-management in government but has not come out for or against the package yet. Meantime union members, nonmembers and the leaders of federal agencies and federal unions are very, very interested in the bill because it ultimately will have a major impact on their power and their pockets.