"Just a handful of issues are still left on the table," said John Fageaux Jr., head of Local 63 of the Office Clerical Unit of the International Longshore Warehouse Union.

The 15,000-member ILWU has indicated that longshoremen 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 United States.

The issues yet to be resolved include wages, job security and pension benefits, Fageaux said. He was hopeful progress could be made.

The start of negotiations was delayed for several hours before beginning in the early afternoon.

"Everybody's working," said Steve Berry, lead negotiator for the 14 marine terminal operators and other firms who employ the office clerks.

The clerks union had warned that a strike would occur if no deal was reached by 12:01 a.m. Monday, but negotiations continued after the deadline. The union gave employers a counterproposal before talks recessed late Monday.

The union was awaiting a response to that offer on Wednesday, Fageaux said.

A work stoppage could create ripple effects throughout many industries that depend on timely movement of cargo. It also would come as the ports enter their busy pre-holiday season, when shippers depend on the facilities to handle imports.

The clerks work at marine terminals and handle bookings for the export of cargo and other transport documents.