If you are one of the 400,000 federal workers involved in a commercial activity--from dispensing pills to fixing tires, making movies or running a computer--your job may be a prime target for takeover by a private contractor.

New guidelines being developed for the White House--reported here Friday--would, if adopted, encourage federal agencies to contract out several billion dollars of in-house federal work to industry.

The guidelines, drafted at the Office of Management and Budget, would require agencies to justify decisions to keep commercial operations instead of turning them over to contractors. They would give agency heads broad powers to farm out work (with or without cost comparisons) to the private sector, which now provides about $6 billion worth of services each year for Uncle Sam.

Commercial and industrial activities include, but are not limited to, things like photography, automatic data processing and computer services, various kinds of maintenance from jet engines to car oil changes, communications, operation of recreational areas and storage facilities, manufacturing and testing, real estate, human and animal health services, printing and guard jobs and many clerical functions from messenger to steno.

When he saw the proposed contracting guidelines, National Federation of Federal Employees chief James M. Peirce fired off a letter to Donald E. Sowle, impolitely inviting him to leave OMB's Office of Federal Procurement Policy and return to the private life.

Peirce says the proposed revision of federal contracting procedures "is perhaps the most blatant attempt yet to funnel federal revenues to private industry at the expense of the American taxpayer. Indeed, cost would no longer be a consideration in most decisions to transfer in-house functions to private contract."

The guides would force agencies to justify by 1983 keeping many key functions in-house.

An aide to Sowle told this column that "it is the policy of this administration to make a concerted effort to get government out of competition with the private sector." He said most U.S. functions "that are in direct competition with industry are candidates" for contracting out.

But he stressed that the guidelines, which are already being scrutinized by one House subcommittee, are still in the draft stage. He said there could be changes in them before they are presented to the White House for final approval.