The Columbia Typographical Union, asserting that The Washington Star's current negotiations violate an existing labor agreement, asked a federal judge yesterday to prohibit The Star from carrying out its threat to close the newspaper on New Year's Day.

During a hurriedly scheduled hearing late yesterday afternoon in U.S. District Court, the union, which represents about 175 Star printers, urged Judge Charles R. Richey to grant an injunction barring The Star from closing and to order The Star to submit "the question of whether it may cease publication" to an arbitration panel.

After about an hour of legal argument between union and Star lawyers, Richey scheduled another hearing for this morning and said he would issue a ruling shortly.

Time Inc., the publishing company that purchased The Star earlier this year, has announced it will close the newspaper Jan. 1 unless it has completed new five-year labor contracts with all 11 unions that represent 1,270 full-time Star employes before then.

Columbia Typographical Union No. 101 has been engaged in what union leaders have described as among the sharpest contract disagreements with The Star during the current negotiations.In a legal memorandum yesterday, the union charged that The Star has made "sweeping demands for surrender of existing contract rights."

Central to the dispute, according to union officials, is The Star management's proposal to eliminate 80 printing jobs by June and reduce the printing staff to as few as 25 employes during the next five years.

Management has offered "buyouts," amounting to $40,000 each, for any printer who gives up his job, union officials have said. Union leaders object to the plan, however, partly because they say printers would be "forced" to quit their jobs and that such compulsory layoffs would abrogate their existing contract with The Star, which guarantees lifetime jobs for printers.

The Star's management has declined to comment on its negotiations with the CTU or other unions.

Although all 11 unions representing Star employes have contracts scheduled to remain in effect until late next year, The Star's management has sought to replace the existing pacts with severely modified new agreements intended to guarantee five years of labor stability. The CTU's current contract expires Sept. 30. In demanding the new contracts, Time Inc. officials have noted that the newspaper's current losses amount to about $10 million a year.

In seeking the federal injunction yesterday to stop The Star from closing, the printers' union cited several provisions of its existing contract. One clause prohibits any "interruption of normal employment or production during the life" of the present contract. A second provision requires arbitration of disputes. A third clause says the "status quo" must be maintained until arbitration is completed.

"We're asking the court to order arbitration and maintain the status quo pending arbitration," George B. Driesen, a lawyer representing the union, told Judge Richey.

Andrew M. Kramer, a lawyer representing The Star, countered by questioning the court's "jurisdiction" to issue such an injunction, by describing the union's claims as "speculative" and by arguing that The Star has "never said we won't arbitrate."

The typographical union's legal move took place as some other major unions took steps to conclude new contracts before Sunday's deadline. The Washington-Baltimore Newspaper Guild, which represents about 475 news. clerical, advertising and other white-collar workers, has reached a ten ative contract agreement and has scheduled a meeting today at which its members will vote either to ratify or reject it.

Local 639 of the International Brotherhood of Teamsters has approved a new contract covering nearly 300 delivery truck drivers and other circulation employes. Teamsters officials have said another negotiating session is scheduled for today in an attempt to reach agreement on two other contracts for an estimated 150 to 200 circulation and other blue-collar workers.

Mailers Local 29, which represents about 70 workers who bundle and sort newspapers for delivery, have continued steady negotiations. "We hope to be able to get it resolved," John D. Daly, president of the local, said yesterday, noting that a bargaining session was set for today. "We're meeting, let's put it that way. As long as we're meeting there's always hope."

In addition to the printers' union negotiations, bargaining between The Star and the Newspaper and Graphic Communications Union Local 6, which represents about 85 full-time Star pressmen, has been described by union leaders as facing the stiffest obstacles. Local 6 officials said yesterday that their talks had recessed and declined to comment further.

Several small unions have either announced new contracts or said they are close to agreement.

Two lodges of the International Association of Machinists and Aerospace Workers -- representing 20 garage mechanics at The Star and nine machinists who repair presses and other equipment -- announced ratification of new contracts yesterday.

Robert Pruett, a union business representative, said the contracts provided for weekly increases in wages and fringe benefits amounting to $40 on Jan. 1, $39 a year later and $40 in 1981. Machinists now earn $318.70 a week.

Unions representing 22 maintenance workers and eight electricians have also been reported by Star and Union officials to have reached at least tentative accord.