The D.C. City Council, with Chairman Arrington Dixon adopting a strong-man role, voted 6 to 5 yesterday to block a public referendum next fall on the proposed downtown convention center.

Supporters of the center, including Mayor Marion Barry-who watched the proceedings while standing in the rear of the chamber-were buoyed by the action. But its foes promptly announced that they would challenge the council's action in court.

"This action is blatantly improper and open to legal challenge," council member Betty Ann Kane (D-At Large) declared. "It was a steamroller," member Hilda Mason (Statehood-At Large) asserted.

In voting to block a convention center referendum, the Council rejected legal advice from James M. Christian, its new general counsel and Dixon appointee serving his second day on the job.

Christian said he agreed with David A. Clarke (D-Ward 1), chairman of the council's judiciary committee, who contended that the council would exceed its authority under the city's home rule charter if it adopted the restriction against the referendum as proposed by Dixon.

Clarke said the council cannot adopt any law that is, more restrictive than the city charter.

The vote came on an amendment to a bill, passed yesterday by the council, that will set up the machinery for new initiative, referendum and recall procedures.

Under those procedures, authorized by amendments to the city charter approved by District voters in 1977 and by Congress in 1978, voters in the future may use the ballot to enact laws, to block actions by the city council and to remove elected officeholders.

The amended charter clearly does not permit referendums on the city's annual operating budgets, but appears to permit such public votes on construction projects-such as the $99-million convention center-that are financed by public borrowing. Dixon's amendment would prevent votes on construction projects.

Barry, backed by Dixon, has contended that referendums on capital construction projects would be disruptive to city operations. Both have sided with business and labor groups who view the conventional center as a spark plug for downtown revival.

The probject, to be located on a three-block site south of New York Avenue NW near Mount Vernon Square, has been approved by the council and partly financed by a federal loan authorized by Congress. The entire site has been acquired by the city, mostly by condemnation.

During yesterday's debate, Kane read from a transcript of a council committee meeting on March 16, 1977, at which Barry-then a council member-declared that he was "not for excluding capital projects from referendum, that ought to be clear."

Dixon insisted yesterday that he was trying to set up a workable process for referendums, not merely to block a vote on the convention center.

After yesterday's 6 to 5 vote on the restrictive amendement, Dixon ruled that the action was technical, not a matter of substance. That meant that the bill goes immediately to the mayor for his signature, then to Congress for review. If Dixon had ruled the action to be substantial, a two-week delay would have been required before final council action on the bill.

Asked by a reporter why he ruled the amendment to be technical, Dixon replied: "Prerogative of the chair".

Council member Nadine P. Winter (D-Ward 6) abstained from yesterday's vote, complaining about Dixon' surprise amendment, and thus permitted the Dixon-led members to prevail.

John Phelan, chairman of the Convention Center Referdum Committee, said his group would challenge the council action in court in an attempt to force a vote on Nov. 6 on whether to cut off further funds for the project. The group, which views the center as a probable money-loser, was rebuffed in an earlier attempt in court to force a referendum on May 1.

Joining with Dixon to support his amendment were Willie J. Hardy (D-Ward 7), Jerry A. Moore Jr. (R-At Large), Wilhelmina J. Rolark (D-Ward 8), William R. Spaulding (D-Ward 5) and John A. Wilson (D-Ward 2). Opposed were Clarke, Kane, Mason, John L. Ray (D-At Large) and Polly shackleton (D-Ward 3). The council currently has one vacancy.