The man who partially plugged the growth valve of the bureaucracy now fears taxpayers (and their wallets) are in even graver danger from a giant "shadow work force" of private contractors.

Rep. Jim Leach (R-Iowa) says uncounted legions of privately-controlled but federally-funded contract workers have become - at a multi-billion dollar price - "the bureaucracy's bureaucracy."

Leach authored an amendment to the civil service reform act that temporarily restricts job growth in government.

With Congress passing new laws hourly, and world-saving projects spewing forth from Washington in a steady steam, the order to gradually reduce the payroll caused panic in some government agencies. But in others, old hands who have been through this before simply reached for forms and ordered up new bodies from outside government to get things done.

Although the government can profile its own bureaucracy by race, sex and age, can tell who is a veteran, lefthanded or head of a car pool, few government agencies have any idea how many nonfederal people work for them. Or what they are paid. Or often, what they are doing.

Leach now is warning Congress that unless it gets a handle on contract employment, it may face a new taxpayers' revolt. He says the non-federal side of federal employment is "so large we have no idea of its true size; so powerful we have no control over conflicts of interest; and so inaccessible we have no way of hold if accountable."

From 1970 to 1978, Leach says, government grants and contracts grew 130 percent to $150 billion. During the same time civilian federal payroll costs jumped only 55 percent to $45 billion.

Leach says he is finding it almost impossible to get figures from any federal department as to the extent of its contracting out. He is in good company.

Back in May, the National Journal's Barbara Blumenthal did an excellent article about the government's "invisible" employes. She estimated there may be four workers "outside" who are paid directly by government for every one listed on the actual federal payroll.

Attempting to get data from government on contract employes, Blumenthal ran into the following excuses:

Veterans Administration (the second largest federal agency) said there was "no way" it could tell how many contract employes it supported.

The Justice Department said it could be done, but it would cost $10,000 to $15,000 to compile the data. Blumenthal's research budget could not handle the amount.

Even the relatively small Bureau of Indian Affairs, with a piddling (by government standards) half-million dollars in contracts, said it would take a team three to six months to find out how many outsiders are on the payroll.

Leach is pressing Congress to force agencies and departments to come up with reliable systems that will allow them to constantly monitor the number and cost of private contractors. And he hopes the Carter administration, which recently has loosened guidelines for contract personnel, will begin to exercise restraints over the bureaucracy's giant second cousin, private industry bureaucrats.