The president of New Caledonia's southern province, Philippe Gomes, has launched a defamation claim against the leaders of the Kanak Rheebu Nuu group.
This comes after the Rheebu Nuu leaders alleged, in a complaint filed last week, that Mr Gomes had mixed politics and business and acted corruptly in getting a contract for his private firm with the Goro Nickel company.
The Rheebu Nuu group is opposed to the two-billion US dollar Goro project for environmental reasons and two months ago caused 10 million US dollars in damage in a weekend sabotage at the Goro construction site.
Mr Gomes says the two leaders, Raphael Mapou and Andre Vama, will use any method in a bid to stop the Goro project.
The two also accused the director of Goro Nickel, Ron Renton, of corruption which has prompted the company to seek a retraction of the two men's claim.
Another anti-Goro demonstration is planned for next Monday.