A leftwing candidate in the French presidential race Jean-Luc Melenchon says the outcome of New Caledonia's independence referendum is a catastrophe.

He held a news conference after several leading French politicians welcomed Sunday's overwhelming rejection of independence, with just 3.5 percent voting for it.

Melenchon said the government destroyed the consensus process of the 1998 Noumea Accord by imposing a referendum date and triggering a huge abstention by the pro-independence side.

The third and last vote was marked by a turnout of 43 percent, which was about half of last year's figure and meant an illegitimate outcome of a meticulous, decades-long decolonisation process.

He said he now hoped the government wouldn't go from what he described as one 'brutality' to the next and warned against imposing change.

Melenchon said President Emmanuel Macron was wrong to claim right after the plebiscite that the Accord was no longer legally valid.

"The current statute of New Caledonia is in the French constitution. it cannot be changed without changing the constitution. Therefore the territory's goverment and assembly remain the legitimate institutions," he said.

Melenchon said by pushing through the referendum, the government made a serious error and returned the territory to the rifts of the late 1980s.

We are now it what is being considered a conflict zone by the Anglosaxon alliance of New Zealanders, Americans and Australians. If the French government thought it could get rid of a problem by being more present and quicker in the Cold War it wants to have with China, it has made a big mistake."

Lecornu acknowledges divisions

The French overseas minister Sebastien Lecornu said the binary dimension of New Caledonia's politics, as seen after Sunday's independence referendum, satisfies no-one.

Speaking in Noumea, he said the legal validity of the vote could not be questioned because under the Noumea Accord, there was no obligation to vote and no quorom.

However, he said politically speaking, the abstention by the pro-independence camp showed a division.

The minister, who set the referendum date despite objections by pro-independence leaders, said the vote was a historic moment.

Lecornu planned to meet the New Caledonian government and Congress this week to discuss the government's financial situation.