The General Services Administration has taken steps to tighten its procedures for awarding contracts to repair and alter federal buildings, Jay Solomon, administrator of GSA, said yesterday.

Responding to a report in yesterday's editions of The Washington Post that GSA and FBI investigations had uncovered more than $2 million in contracts awarded here to nonexistent companies and companies that do not do the work paid for, Solomon said, "I want to emphasize that GSA officials discovered these improperties themselves and took appropriate action."

"Indications of fraud were uncovered in some contracting for building repairs, alterations, and services in the Washington area," he said. "These included indications of payments made to nonexistent companies or payments to firms for work they did not perform."

Solomon added, "After GSA's investigators had developed detailed information on alleged contracting irregularities in the Washington area, the findings were turned over to the Justice Department. The investigation here has continued with a GSA management team working closely with the FBI."

The types of fraud uncovered within GSA's public buildings service include contracting for two coats of paint when only one is needed or applied, and awarding contracts to private firms for work actually performed by GSA employes, sources said. Many of the contracts were awarded by GSA building managers, who have authority to award contracts up to amounts of $10,000.

Solomin said GSA had stepped up its surveillance of each contract, contractors' backgrounds, competitive bidding procedures, and inspection of the work once it is completed.