LONG BEACH City Council has voted 6-3 to sack Thomas Fields, president of the Long Beach Board of Harbor Commissioners, in a move prompted by the mayor but over protests from the local shipping community.

Said Mayor Bob Foster: "I have lost confidence in Mr Fields willingness to harmonise the interests of Long Beach with that of the Harbor Department."

Mayor Foster and Mr Fields have disagreed on travel expenses, a new headquarters for the port, and coordination of security at the port between city police and port police.

Said Mr Fields: "Every decision I have made as a member of the commission has been based on what is best for the port and the city."

The Long Beach Press-Telegram said Mr Fields' supporters questioned the timing of the move as the port searches for a new executive director.

Earlier this year, Long Beach executive director Christopher Lytle resigned after little more than a year to take up a new post at Oakland, amid talk of tension over political intervention in port matters.

Long Beach is the second-largest container port in the US, closing the gap with archrival Los Angeles over the past year after winning away some of its customers.

The municipally-owned ports of Long Beach and Los Angeles have been entangled in disputes with their respective mayors with Geraldine Knatz, LA's executive director for eight years, recently shunted off into retirement by Mayor Eric Garcetti.

Dissatisfaction with Ms Knatz as LA's harbour chief was more apparent as the bigger port was losing ground steadily to its neighbour Long Beach and to an alarming extent.

But few are certain why Mayor Foster wants to oust Mr Fields. The dispute has alarmed shipping lines calling at the Port of Long Beach and the global terminal operators that are based at the southern California port, reported London's Lloyd's List.

Said Pacific Merchant Shipping Association (PMSA) president John Laurin: "Mayor Foster has not given the council, the public or port customers any reason to remove Fields, who is well-respected in maritime and logistics circles."

Mr Laurin said Mr Fields was meeting port customers in Asia when he heard that the mayor wanted to remove him.