Los Angeles: US West Coast ports will partially close this weekend due to a dispute between staff and bosses along the key trade frontline with Asia, officials said yesterday.

The Pacific Maritime Association, which represents employers, announced the suspension of loading and unloading of ships at 29 West Coast ports.

Terminal operators can still move containers out of their yards, but the PMA announced the suspension after weeks of union work-to-rule, including in the major ports of Los Angeles, Long Beach and Oakland.

"After three months of union slowdowns, it makes no sense to pay extra for less work, especially if there is no end in sight to the union's actions which needlessly brought West Coast ports to the brink of gridlock," said PMA spokesman Wade Gates.

Operations are scheduled to resume Monday.

A spokesman for the International Longshore and Warehouse Union, representing workers, criticized the "crazy and irresponsible" order.

"Customers need their containers and have already suffered from industry-caused delays and congestion," said the spokesman, Craig Merrilees. Instead of stopping work, "the focus needs to be on resolving the contract and reaching an agreement as soon as possible," he added.

Port productivity has fallen by up to 50 percent, according to PMA boss Jim McKenna, who accused workers of staging an illegal stoppage.

The ILWU denies the claim, saying it is only allowing certified crane operators to work.

Port management and dockworkers have been trying to hammer out an agreement over to renew a contract that expired in July.

The PMA said Wednesday it had made its best offer, raising wages by three percent per year over five years and increasing pensions. But Merrilees said that was not the main point of contention.

In 2012, week-long strike action crippled the ports of Los Angeles and Long Beach, which handle 40 percent of US maritime imports, mainly from Asia.

At the time, the National Retail Federation noted that the recovery from a 10-day lockout of West Coast ports in 2002 took six months and cost the economy an estimated $1 billion a day.