The New Caledonian Kanak Rheebu Nuu group says it is worried that the Goro Nickel mining company is continuing construction at its waste storage site despite a court injunction.
A court in Paris two weeks ago ordered Goro Nickel to stop construction at the waste storage site amid environmental concerns.
Our correspondent in Noumea, Tuo Chinula, says Rheebu Nuu's president, Andre Vama, says he went to the construction site to observe what is happening there.
Tuo Chinula says Mr Vama told her he suspects Goro is secretly continuing construction.
"The Southern province has ordered that Goro Nickel continue works which would ensure the environmental safety on the particular areas and Andre Vama was saying that he thinks the works that are actually taking place now are a continuation of the actual construction process that was meant to have stopped."
Goro Nickel says the southern province has instructed it to continue work before the start of the wet season, because heavy rain could cause serious environmental damage.