The president of New Caledonia's Future Together Party, Didier Leroux, has quit his position, saying he is taking responsibility for the poor results in the provincial elections in May.
The party had been the dominant force after the 2004 polls but was weakened by splits.
Mr Leroux says the party has veered off its original path by joining a coalition with the other anti-independence parties.
"I've always been against that division of public opinion into two blocs, the independentists on one side the anti-independendists on the other side. I think the future together is on the contrary the fact that we have to build a future of this country together."
A successor is to be elected at a party congress before the end of the year.