400 members of the Kanak USTKE union in New Caledonia are providing a round-the-clock guard of the Noumea port run by the company, Sato, following a clash yesterday morning which saw three men taken to hospital.
Up to 40 men armed with metal bars and two fork lift trucks tried to free the port from union members who have blocked the unloading of a ship.
USTKE representative, Pierre Chauvat, says they are in talks with the ship's owners, the Mediterranean Shipping Company, which wants to set up a service between Australia and New Caledonia.
USTKE says if that goes ahead, MSC will undercut local shipping companies threatening up to 200 jobs in the long term.
Mr Chauvat says yesterday's attack could have been much worse.
"We were standing just outside the port peacefully and they came with a big forklift, they hit some police cars but fortunately we managed to stop them before they killed anybody. So that was a real attack by this militia. Since then we reinforced the guard of the port by about four hundred USTKE militants and the ports reopened normally at seven."
MSC says they will take France to the European court of Justice over the way the company is being treated in New Caledonia.