A D.C. City Council committee approved a bill yesterday to revamp the city's controversial contracting and purchasing system, despite efforts by Mayor Marion Barry to delay action on the measure.

The bill, sponsored by council member William Spaulding (D-Ward 5), is aimed at saving millions of dollars annually by centralizing the District's far-flung purchasing and warehousing operations.

Barry contends that the bill, which was first introduced by Spaulding in December 1983, infringes on his power to delegate contracting authority, and he has lobbied intensely against its key provisions. The mayor persuaded Spaulding to withdraw the bill last December to work out some minor problems, and yesterday Barry again urged Spaulding to delay action.

"I think it is important that the committee have the benefit of my thoughts in the legislative formulation process," Barry said in a letter to Spaulding, who is chairman of the Government Operations Committee.

Spaulding said he and his staff repeatedly had sought comments on the bill from Barry's administration but have received nothing in writing. He said he is convinced Barry's request yesterday for additional time amounted to delaying tactics. "It's time that the bill must go forward," Spaulding said.

Under the bill, the city would assign one agency, the Department of Administrative Services, the responsibility for awarding all contracts and purchasing and storing supplies.

Currently, the department has primary responsibility for purchasing, but the heads of most of the city's major departments are empowered to award millions of dollars worth of contracts on their own.

The bill would also require competitive bidding for all purchases above $2,500. The current limit is set at $10,000.

The proposed consolidation of functions has been recommended by experts in numerous studies back to at least 1959.

An investigation last year by The Washington Post showed that the city paid an average of 26 to 79 percent more than nearby jurisdictions for a variety of commonly used supplies because of its lack of a centralized purchasing system.

William Johnson, director of the administrative services department, City Administrator Thomas Downs and the heads of the city's other major departments attended yesterday's committee meeting.

Spaulding would not allow any of the officials to speak until after he and council members Carol Schwartz (R-At Large) and Charlene Drew Jarvis (D-Ward 4), voted 3 to 0 to approve the measure.

"We have not seen the bill and all the amendments," a visibly irritated Johnson told reporters after the committee hearing. "We finally got them when the hearing started."

Johnson said the administration also wanted the committee to postpone its action until the city receives the results of an $80,000 study of its procurement system by the National Academy of Public Administration.

Two committee members, John Ray (D-At Large) and Nadine Winter (D-Ward 6), echoed Johnson's complaint and angrily left the meeting before the vote.

Schwartz said committee members had ample time to consider the changes. "The mayor has been lobbying very hard not to pass the bill," she said.

Spaulding said that a centralized system and computerization of purchasing data, which is also mandated by the bill, would save the city as much as $20 million a year. "The District has let agencies . . . buy . . . in small can sizes at high prices when together they could and should get lower prices," he said.