Philippine President Ferdinand Marcos yesterday halted construction for the second time on a controversial nuclear power plant near Manila, asking the U.S. builder to provided more safety features.

In a statement from the presidential palace, Marcos added that he would pay no more interest on a $644 million loan from the U.S. Export-Import Bank that was floated to finance the $1.1 billion plant. He said he wants westinghouse Power Systems Co. to renegotiate its "iniquitous and onerous" construction contract that involves "an old design plagued with unresolved safety issues."

The future of the plant on Mt. Nation has become entangled in questions of U.S. policy on nuclear exports and on the overseas reach of U.S. safety regulations.

Critics of the plant say it is dangerous because of its location on the slope of an inactive volcano near a known earthquake zone. They say it is being built to the outdated safety specifications of 1973 and includes questionable design features.

These concerns have held up the issuance of an export license for the reactor by the U.S. Nuclear Regulatory Commission despite Westinghouse's contention that the Philippines must set its own safety standards without U.S. interference. The Philippine government has asked to submit comments for NRC consideration in the case.

Westinghouse division president Gordon C. Hurlbert reiterated the company's position yesterday that the 620-megawatt plant is safe. President Marcos' own special investigatory commission, which called for the contract renegotiation, found the location able to withstand any possible earthquake and declared the volcano extinct, Hurlbert said through an aide.

"Under the terms of our contract . . . we stand ready to introduce any pre- or post-Three Mile Island safety changes desired by the customer," Hurlbert added.