A pro-independence delegation from New Caledonia has left for New York to raise its opposition to the December 12 independence referendum with the United Nations.
New Caledonia has been on the UN decolonisation list since 1986.
Because of the pandemic, the pro-independence parties say they will neither take part in the vote, nor recognise its result.
France has refused to postpone the vote despite repeated pleas by pro-independence parties to defer it.
New Caledonia's public broadcaster said the Congress president, Roch Wamytan, left Noumea at the weekend after the pro-independence parties said they would not respect the referendum outcome.
Mr Wamytan was a signatory for a pro-independence party of the 1998 Noumea Accord which provided for three referendums by 2022.
The pro-independence parties wanted the third referendum to be held next year, but Paris decided to hold it this month.
In last year's second referendum, just over 53 percent voted against independence.
Can still be called off says candidate
French presidential candidate Jean-Luc Melenchon says it's not too late to postpone the referendum.
Melenchon said by refusing to defer it to next year, President Emmanuel Macron risks breaking New Caledonia's equilibrium and recreating the conditions of its conflict now kept in check with the Noumea Accord.
The French leftist politician Jean-Luc Melenchon has quit a parliamentary mission to New Caledonia in protest at former prime minister Manuel Valls. Photo: AFP
He said endangering the peace in New Caledonia could be an election strategy for Mr Macron to appear as a law-and-order candidate.
Mr Melenchon has urged him to put a postponement of the referendum on Wednesday's government agenda.
France, which deems the pandemic to be under control, has flown in almost 2,000 extra police, including riot squads, to provide security for the referendum.
The call to postpone the vote is being backed by civil society figures internationally.