New Caledonia's USTKE union has called for a united approach by the pro-independence camp to the May election in the southern province.
This follows an apparent commitment by the pro-independence FLNKS movement to run with a list of candidates without members of the Labour Party.
The Labour Party has already accused the FLNKS of being irresponsible for not including it in its list.
However in the lead-up to last year's referendum on independence from France, the Labour Party called for a boycott while the FLNKS tried to mobilise as many voters as possible.
The FLNKS will meet this weekend for further talks on the election campaign.
As the southern province is the stronghold of the anti-independence camp, there have been calls for a joint list of the rival side to increase the chance of securing more seats.
The elections of the three provincial assemblies in May is predicted to be a close contest, with the pro-independence parties hoping to secure a majority for the first time.
For the election in the Loyalty Islands province, rival anti-independence parties have joined forces in the hope of making inroads into the assembly dominated by the pro-independence side.
The new Congress, which will again be made up of 54 members drawn from the three provincial assemblies, is widely expected to call for another independence referendum.