A District City Council committee voted yesterday to approve an additional $1,146,747 for the operation for the rest of this fiscal year of the D.C. Superior Court and the D.C. Court of Appeals.

In asking for the additional money, Gladys Mack, the city's budget director, said the courts overspending significantly during a time of fiscal crisis for Washington, and that "there is nothing to say" they will not continue the practice if the new money is approved.

The vote yesterday by the council's Judiciary Committee was 3 to 1, with Betty Ann Kane (D-At large) voting no. The full council may take up the proposal next Tuesday. The courts have indicated that they need the money immediately.

The $1,146,747 total breaks down for these expenses: about $649,000 for witness and juror fees, $312,000 to fund pay increases already approved for Superior Court judges, $80,000 for increases for appellate court members, and $105,000 for general payroll purposes.

Even with the extra money, the courts have said, their budgets are so tightly drawn that they may have to close down for five days in September, near the end of fiscal 1980.

Council committee members complained that they had been forced into a no-win corner, with their only choice being approval of the spending of money the city does not have, or the closing of the courts for the summer.

This pending new deficit, Mack said, "now becomes a part of the larger [fiscal] problem" that the mayor will address in his televised speech July 21 that will focus on the budget.

Mack said the city probably would end up borrowing the additional money from the U.S. Treasury.

Larry Polansky, executive officer of the D.C. Courts, said after the meeting that the additional funding would not be enough to pay the salaries of the court staff -- including the judges and their clerks -- for the entire fiscal year.

Polansky said that an additional $200,000 would be needed or funds would run out for at least five days at the end of September. If that happens, he said, the question of whether the courts would stay open would depend on how many employes would be willing to work without pay.