The New Caledonian Kanak USTKE union says it will continue its action in the port of Noumea.
The union took control of the port three weeks ago to stop multi-national shipping giants Maersk and MSC from using the docks.
There are no police or customs at the port at present.
An USTKE spokesperson, Pierre Chauvat, says they will continue to prevent MSC from docking until a solution is found.
"Yes, yes, today the port is open. It is only MSC that is still blocked. Everything else is free to move in and out of the port."
Maersk left New Caledonia on the weekend, saying international security standards are not met.
Mr Chauvat says the French High Commission has not sent police to the port.
Earlier, the High Commission said it was awaiting a decision from Paris over whether to send in police.
And MSC has said it will take France to court over the situation at the New Caledonian port.