The D.C. School Board, faced with a Wednesday deadline for a possible teachers strike, declined last night to remove the threat by extending the teachers' present contract.

The board decided against any extension after being told little progress had been made in negotiations on a new contract with the Washington Teachers Union.

Board Vice President Carol L. Schwartz (Ward 3) noted that the possibility of a strike had been a "constant threat" since schools opened in September, but said the board "can't lie down and play dead" in bargaining.

The threat of a walkout by the teachers on Wednesday was posed last week by union President William Simons, who said that unless the contract is extended, "there will be a strike."

In an interview last night, Simons said he had not yet been formally told of the outcome of the school board meeting, and the declined to predict flatly that there would be a strike Wednesday.

"I can't answer that at the moment," he said when asked if the teachers would walk out on Wednesday. However, Simons reiterated his postion that "our teachers are not going to work with out a contract."

A union meeting would have to be held before a strike could be called. Simons observed that whether such a meeting could be held before Wednesday "depends on the weatherman," a reference to yesterday's heavy snow.

The Wednesday deadline was the consequence of an action last month in which the school board agreed to extend for a third time the expired contract with the teachers' union.

Several school board members subsequently said they would be opposed to any further extension if they were told by their negotiators at last night's meeting that contract talks had not progressed.

The agreement reached in January called for 15 days of negotiation with the help of a federal mediator. Factfinding was to follow in the event of a deadlock.

Simons blamed lack of progress in the talks on what he called "stonewalling" by the board. "They don't want to move," he said.

Schwartz said she believed the union liked its current contract and wished to keep it.

Some board members have contended that to improve education they must get tighter control over school operations and win back concessions made to the union in past contracts.

While asserting that the union would not work without a contract, Simons said neverthless he was prepared to negotiate as long as necessary.