Uncertainty surrounds the legality of next week's planned fresh elections in New Caledonia's Loyalty Islands province.
The results of the polls in May were annulled by the French supreme court which upheld a complaint by the Labour Party after it claimed that irregularities with the proxy votes affected the outcome.
The Labour leader, Louis Kotra Uregei, has now challenged the candidacy of the anti-independence camp's Simon Loueckhote, saying he cannot stand because he was a candidate in the southern province in the May polls.
Labour argues that next week's election is part of the overall general election.
Mr Loueckhote says he is allowed to switch from one provincial assembly to another.
The possible legal challenges may not be resolved before voters go to the polls at the end of next week.