Members of the USTKE union are to inspect the Goro Nickel site in New Caledonia next week to establish whether the company is flouting a Paris court ruling.
An injunction was issued in France stopping Goro Nickel from carrying out any more work on the storage site of its nickel mining project after the kanak activist group, Rheebu Nuu, claimed it would damage the environment.
But the company says that work is continuing after the southern province instructed it to carry on saying that stopping construction now could cause environmental damage in case of heavy rainfall.
Pierre Chauvat from USTKE says the law cannot be ignored in this way.
"In terms of law it cannot be overruled. Once there is this law that has been given, you cannot outrule it. And I think that Rheebu Nuu will demand not to outrule this court decision."
In the meantime, Mr Chauvat says the Employment minister has posted a full time employment officer at the plant to ensure that the filipino workforce are receiving appropriate pay and conditions.