Active duty and retired U.S. workers would be forced to take one-third of the proposed $15 billion federal spending cuts out of their pay or pension checks if the powerful House Budget Committee sticks to the economizing plan it has in the works.

The cutbacks, in the form of a reconciliation resolution, would reduce budget outlays from those proposed in President Carter's final budget. One of every three dollars in those cuts would come from the people side of government, in the form of smaller raises, retirement and fringe-benefit changes (worth $5.8 billion) for present and former bureaucrats.

Under the new budget system, the Senate and House Budget committees set spending levels. If the respective houses approve the levels, then committees that have jurisdiction over various agencies and programs must legislate matching dollar cuts. In the case of federal and postal workers, the proposed cuts that would be assigned to their jurisdictional committee -- the House Post Office-Civil Service Committee -- amount to one-third of the total proposed government spending cut.

The Post Office-Civil Service unit, headed by Rep. Bill Ford (D-Mich.), could make the cuts any way it chose, as long as the reductions were the same as those in the proposed reconciliation. It has been "suggested" that the committee go along with the 4.8 percent raise President Reagan has proposed for this October for white collar government workers, instead of the 5.5 percent Carter suggested.And it has been proposed that the committee could produce $750 million in retirement savings if it limited civilian government retirees to one cost-of-living raise a year, instead of raises every six months. (The Armed Services Committee will get the same suggestion for military retirees.)

The committee is also under the gun to reduce subsidies to the U.S. Postal Service (that could mean service and job cutbacks), and to reduce government payments to some employe insurance programs, make changes in annual leave, raise the early retirement age and perhaps limit the income of so-called double-dippers, retired military personnel who now work as federal civilians.

None of the suggestions will be binding when the House approves a reconciliation bill. But the dollar cut-backs assigned to the Post Office-Civil Service Committee will be binding. As a practical matter, the committee would probably have to go along with most of the "suggestions" to meet the ceilings.

Federal, postal and retiree-group lobbyists are working on the House Budget Committee, controlled by the Democrats, in hopes it will reduce the amount of proposed spending cuts and not require government employes and retirees to absorb so much of the cuts. A decision is due this week or early next.