LONG BEACH, Calif. — A negotiator said yesterday that slow progress was being made on a new contract between 750 clerical workers and shipping companies at the nation's busiest cargo gateway.

Negotiators are still aiming to resolve key differences on wages, pension benefits and other issues.

The 15,000-member ILWU has indicated that longshore workers would honor picket lines if the 750 clerks strike.

That would effectively shut down loading and unloading operations at the neighboring ports of Los Angeles and Long Beach, which account for 40 percent of all the cargo container traffic coming into the U.S.

Steve Berry, lead negotiator for the 14 marine terminal operators and other employers, said negotiators spent much of the day discussing issues specific to each company and its workers.

"We're making progress," Berry said. "We're not there yet. We're moving forward, not backward."