Reports from New Caledonia say police have dropped their arrest warrants for two leaders of the Kanak Rheebu Nuu group, Raphael Mapou and Andre Vama.
The two had been wanted following the destruction by Rheebu Nuu members of vehicles and installations at the Goro Nickel mine and construction site in the territory's south.
The action was reportedly aimed at stopping pollution of the environment and caused damage worth 10 million US dollars.
Several people were arrested after clashes between activists and riot police, prompting the site's closure for three weeks.
The Kanak Development Agency now says Mr Mapou was allowed to go free after a day's questioning.
It says police dropped their warrants after the two leaders wrote a letter to the investigating judge explaining the reason for their action.
Work on the site has resumed, with French police guarding key positions around the clock.