Pan American World Airways yesterday asked the Civil Aeronautics Board for authority to carry passengers between New York and San Francisco or Los Angeles at cut-rate fares.

The international carrier, which currently has no authority to fly domestic routes, operates weekly flights from New York to the West Coast, Auckland, New Zealand, and Sydney, Australia.

While the flights bwtween West Coast cities and the South Pacific are heavily patronized Pan Am may carry riders between New York and the West Coast only if they are traveling to or from Auckland and Sydney. As a result, most seats on the transcontinental flights are empty.

Pan Am said it is seeking authority to provide "low fare continental service" on the New York-West Coast flights and a spokesman said that if the CAB approves, the frequency of service could be increased.

A greater number of weekly flights has been impossible "because of the diseconomy of a 'closed door' restriction between New York and California . . . to operate without traffic rights is waste in every sense: denial of service to the public, waste of resources and diseconomy for Pan American," the company said.

Technically, Pan Am's proposal to the CAB was part of a proceeding before that agency on an application of World Airways, a charter airline, to fly coast to coast with low fares. Because World is not a scheduled airline the CAB originally dismissed the charter company's bid. A federal appeals court said in December that the CAB had misread the law, however, and ordered the agency to address the application on its merits - a task begun by the CAB on Jan. 14.

In its intital application, World proposed a coast-to-coast fare of as low as S89, about half the current charge. A Pan Am spokesman said yesterday his company had not proposed any specific fare.