The Philippine Cabinet decided today not to start operating a $2.1 billion nuclear power plant supplied by Westinghouse Electric Corp. that has been kept closed because of unresolved questions about its safety and cost.

The Cabinet, which has been debating the issue for weeks, issued a statement after its weekly session saying a five-person committee headed by presidential spokesman Rene Saguisag will negotiate with "all parties concerned" on the legal and financial aspects of the freeze. Saguisag said the Cabinet agreed to "mothball the plant," located in Bataan Province, about 30 miles northwest of Manila.

Saguisag, an opponent of nuclear power, told reporters that the Soviet nuclear power plant disaster "certainly did not help the cause" of that power source here. "We want to spare our own people from the same tragedy," Saguisag said.

Construction of the plant, which is almost completed, was begun under deposed president Ferdinand Marcos. The contract for the 620-megawatt plant was signed with Westinghouse in 1976 for $1.1 billion. It has since grown to $2.1 billion. Antinuclear groups have criticized cost overruns and questioned plant safety.

Saguisag pointed out that President Corazon Aquino had promised in her campaign to scrap the plant. "If we go ahead now, we may have an uprising on our hands," he added. But several in the Cabinet have stressed the obligation to repay foreign loans. The U.S. Export-Import Bank financed the contract with $277 million in direct loans and $676 million in loan guarantees.

Government investigators are reviewing the legality of the contract with Westinghouse. A federal grand jury in Pittsburgh is investigating commissions paid by the company.