New Caledonia's Union of Kanak and Exploited Workers says it won't allow two large international sea freight companies access to the main port in Noumea.
USTKE has been blockading two companies, Maersk and the Mediterranean Shipping Company, from the port, saying their operations there would jeopardise regional companies and local port workers.
USTKE spokesman Pierre Chauvat says they object to the companies' dropping their prices of freight between New Zealand and Australia.
He says this means the local companies would be unable to compete with them, and local people would lose jobs.
Mr Chauvat says the Maersk ship has already pulled away from Noumea, and they're waiting for the MSC ship to also leave before opening the port again.
"The global volume of containers to be treated is so small that the companies that operated in the Pacific region are much more than enough; and by having those two companies in addition to what's existing will jeopardise the regional sea freight ship which is PDL and Sofrana, and all the workers that operate on the docks in Noumea."