Port clerks and their employers at the US ports of Long Beach and Los Angeles have tentatively agreed on a new contract, averting strike action that could have led to port closures and possibly prevented retailers shelves being filled ahead of the holiday season.

"The employers are pleased that the union recognised the substantial investment that (employers) have made and agreed to their last wage proposal," said Steve Berry, a negotiator for the shippers.

John Fageaux, the union's lead negotiator welcomed the deal as "great news," reports the Associated Press. "Both sides worked very, very hard in an effort to not have a strike," he said. "The last thing the union wanted to do was to put people out of work and have such a devastating effect on the local and national economy."

The deal with the Office Clerical Unit, Local 63, of the International Longshore and Warehouse Union comes after talks over a new contract agreement broke down.

The 15,000-member ILWU had said that longshoremen at the port would honour picket lines if the 750 clerical workers went on strike, which would have effectively shut down the port to cargo traffic.

Shipping companies and retailers across the country were also relieved, Mr Berry said.

"They're greatly relieved because holiday goods are arriving now and this gives them confidence that the flow of goods is going to continue uninterrupted," he said.

The deal gives workers a US$2.50 per hour raise over three years until the end of the decade and gives employers some flexibility in their staffing levels. Mr Fageaux added in the report that union members will vote on the labour agreement early next week.