WASHINGTON (AP) _ U.S. and Japanese negotiators were completing final details Monday on an agreement to defuse a tense shipping dispute.

Undersecretary of State Stuart Eizenstat and Japanese Ambassador Kunihiko Saito met through the weekend to complete an ``agreement in principle,'' which both men had announced on Friday to head off the banning of Japanese cargo ships from U.S. ports.

State Department spokesman James Rubin said that the weekend negotiations did not signal problems with the accord, which is designed to eliminate expensive port restrictions that American shippers have long complained about.

``We expect a comprehensive agreement to be reached very shortly,'' Rubin told reporters. Other officials indicated that State and the Transportation Department would probably hold a joint news conference Tuesday to announce completion of the negotiations.

Officials of the Federal Maritime Administration, the small government agency that triggered last week's crisis by ordering Japanese ships barred from U.S. harbors, said they were waiting to review the final agreement.

The commission must decide what to do about forcing Japan's three major shipping lines to pay $4 million in fines that were imposed when the Japanese government refused to reform port practices. It was a failure by the shipping lines to pay those fines that precipitated the order to block Japanese ships from American ports.

``Once an agreement is reached, we will stay on top of the situation to ensure that the implementation continues to progress satisfactorily,'' said Bruce Dombrowski, a commission attorney.

The dispute centered around the monopoly control over port activities exercised by the Japan Harbor Transport Association, a group of stevedore companies that dictated when ships could dock and which stevedores they had to use.