A special fraud prevention unit, complete with a hot-line telephone that informants in and out of government may use to pass on tips of waste and corruption in government, is being set up by the General Accounting Office.

Joe Boyd, a 25-year veteran of the congressional watchdog agency, will head the 40-memeber section. It will have special investigators in different agencies, and specialize in spotting loopholes in agency computer and funding operations. Through a combination of fraud, indifference and ignorance, U.S. agencies routinely crank out hundreds of millions of dollars each year for bogus overtime, and in making payments to contractors or grantees who don't deliver.

On Monday this column reported a GAO spot check of six agencies, which indicated that $4.2 billion in potential overpayments to contractors and grantees had not been collected because officials were "too busy" to recover the money.)

GAO head Elmer B. Staats created the new unti-the Special Task Force for Prevention of Fraud - as a followup to earlier GAO exposes of the shocking state of government contact policies.

The all-important telephone number whistle-blowers can use to pass on hot items is 275-5401. That is going to be a very, very busy line, so make sure you have a good item.

Labor Department is setting up its own Fraud and Abuse Prevention Survey aimed at spotting money problems. It was one of the agencies cited by GAO as being overly forgiving of contractors and grantees who were overpaid for services.

He Must Light Up Their Lives. Some staffers in the Commerce Department's public affairs shop have nicknamed their boss, ex-Washington reporter and Mondale aide Ernest A. Lotito, the "Roman Rocket."

Joe Vacca: Friends of the out-going Letter Carriers union president gave him a testimonial last night at the Touchdown Club. He deserved the tributes. Vacca and most other Washington officers of the union were swept out of office in the recent mail ballot. Members were unhappy about the contract with the postal Service and its nearly 600,000 rank-and-file workers. Ironically, the "bad" contract that tripped up Vacca and other officers who helped work it out provides lifetime job guarantees for other postal employes.

Warren Irons, long-time executive director of the Civil Service Commission, died last week in a Florida nursing home. He was the top career man at CSC from 1958 to 1965, and set a standard for integrity that is hard to top. Mr Irons won every major award possible for distinguished civil service, and served with the Ford Foundation in Kenya after the retired.

Charity Countdown: This is the final week for the metro Washington area's combined Federal Campaign. The one-shot charity drive is still short of its $12.5 million goal.

Presidents of the two largest federal unions have endorsed the CPC approach to giving. President Carter's cousin Hugh has been personally riding herd on the White House section of the fund drive, and contributions there are up. Everybody is being urged to give. But pressure, which in past years was a problem, appears minimal in most agencies this year.

If you have not signed a pledge card yet and want to, time is running out. Details on the CFC and its goals from the headquarters staff at 488-2087.

Clerk-Typists: HEW in Rockville has several Grade 3 and 4 openings. Call Dick Boston at 443-4826.

General Services Administration has named Dale R. Babione, a former top Defense official, as acting assistant administrator for acquisition policy. GSA buys millions of dollars worth of goods and property each year as the government's chief housekeeper.

Working under Babione, each heading major directorates on an acting basis will be Philip G. Read and Bertrand G. Berube, both GSA veterans, and Harold Scheller, who comes over from Defense Logistics Agency and Peter Kayafus from the Air Force Systems Command.