The union representing around 900 clerical workers from 14 shippers and terminal operators at the ports of Los Angeles and Long Beach have resumed labour talks after two unsuccessful meetings on Friday and Sunday last week.

Clerical workers are worried they could lose their jobs to outsourcing and are asking for a guarantee of job security.

Employers have said that the union's demands of "feather-bedding" are unrealistic as they would hamper the companies from operating efficiently.

"Feather-bedding" provisions include a measure that would require shippers to hire temporary and permanent workers even if there is no work available.

Union officials have added that they feared local jobs could be lost because the terminal operators wanted to implement a new computer system that would allow customers to directly access booking information.

Office workers representing International Longshore and Warehouse Union started picketing Thursday midnight after a three-year labour agreement expired with the Los Angeles/Long Beach Harbor Employers Association.

Shipping traffic has not been affected as clerical work is normally cleared several days in advance and only two out of the 14 shipping companies are on strike.