The Metro system has rejected all bids on a proposed contract to construct a parking garage and a section of a subway tunnel in Anacostia for the long-delayed Green Line, transit officials announced yesterday.

The move marked the second time the agency has canceled bids on the $11 million project and the latest in a series of conflicts over the Green Line, the only unopened route in the planned 103-mile subway system.

Metro officials said the bids were nullified because of inadvertent errors by the transit authority in carrying out federal rules governing minimum wage levels. But they also cited problems in gaining adequate participation in the project by minority-owned businesses -- a recurrent issue in recent months.

Transit officials described the 215-foot tunnel section included in the project as "critical" to Metro's plan to open the Green Line by 1990. The proposed three-story, 1,000-space garage is to be built at the planned Anacostia station, near the Anacostia Freeway (I-295) and Howard Road SE.

In an attempt to avoid further delays, the agency's board of directors scheduled an accelerated third round of bidding.

Metro's actions drew immediate criticism from the construction group that had submitted the lowest bid, a joint venture formed by A.A. Beiro Construction Co. Inc. of Alexandria and Perdomo and Associates Inc., a Hispanic-owned Washington firm. The companies' bid was $11.9 million.

Eduardo E. Perdomo, president of the minority-owned firm, denounced Metro for rejecting the bids. "They don't have a real reason for doing it and they are looking for technicalities," he said, terming the move "unfair" and "discriminatory."

Bill Euille, vice president and controller for Beiro, said the companies had complied with minority requirements. "The bids should not have been rejected," he said

Beiro submitted an $11 million bid last February, the lowest of eight bids. Metro threw out the bids, saying minority requirements were been met. In the second round, Beiro formed the joint venture with Perdomo and raised the initial price by almost $900,000.