More than 200 "rioters" have been arrested since the clashes broke out.
France deployed troops to New Caledonia's ports and international airport, banned TikTok and imposed a state of emergency on Thursday after three nights of clashes that have left four dead and hundreds wounded.
Pro-independence, largely indigenous protests against a French plan to impose new voting rules on its Pacific archipelago have spiralled into the deadliest violence since the 1980s, with a police officer among several killed by gunfire.
Palm-lined boulevards, usually thronged with tourists, were littered with debris and patrolled by armoured vehicles, while some fearful locals piled up household objects to make roadblocks.
There was a suspected arson attack on the building housing a consultative body for the indigenous Kanak people, its communications staff said, although the extent of the damage was not immediately clear.
As part of a sweeping French response, security forces placed five suspected ringleaders under house arrest, according to a statement by the high commission, which represents the French state in New Caledonia.
House searches would be carried out "in the coming hours", it said.
More than 200 "rioters" have been arrested since the clashes broke out, the high commission said, numbering participants at up to 5,000 in greater Noumea.
It added that "people have been ambushing law enforcement officers" with "sustained fire from hunting rifles".
Hundreds of people, including 64 police, have been wounded, officials said, among the territory's population of around 270,000.
'We need milk'
French authorities reported a third night of "clashes", although AFP correspondents in the streets of the capital, Noumea, said it appeared calmer than previous nights.
Onlookers wandered around the husks of burnt-out shops with twisted shutters, looted shelves and discarded packaging.
"We just grabbed what there was in the shops to eat. Soon there will be no more shops," said one woman in a suburb of the capital, who spoke on condition of anonymity.
"We need milk for the children. I don't see it as looting," she told AFP.
France is establishing an "air bridge", the high commission said, to rapidly move in troops and police reinforcements but also to bring in essential supplies for the population.
In Paris, French President Emmanuel Macron offered to hold talks on Thursday with New Caledonian lawmakers and called for a resumption of political dialogue.
Sonia Backes, the leader of New Caledonia's southern province which includes Noumea, has already written to Prime Minister Gabriel Attal asking for a 150-million-euro ($163-million) "one-off reconstruction fund" to repair the damage.
She added that the state of emergency would give hope to people affected by "this wave of hate and barbarity".
Interior Minister Gerald Darmanin on Thursday accused Russia-friendly Azerbaijan of "interference" in the unrest but did not expand on what he meant.
TikTok ban
Attal told a ministerial crisis meeting that troops had been deployed to secure ports and the international airport in New Caledonia, which has been closed to commercial flights.
TikTok had been banned because it was being used by protesters, he said.
By Thursday morning, AFP could identify fewer than 20 accounts related to the violence on the platform.
New Caledonia, which lies between Australia and Fiji, is one of several territories around the globe that remain largely under French control in the post-colonial era.
Colonised by France from the second half of the 19th century, it has special status, unlike the country's other overseas territories.
While it has on three occasions rejected independence in referendums, independence retains strong support among the Kanak people, whose ancestors have lived on the islands for thousands of years.
The state of emergency enables authorities to enforce travel bans, house arrests and searches.
Along with a night curfew, there are bans on gatherings, the carrying of weapons and the sale of alcohol.
Nearly 1,800 law enforcement officers have been mobilised and a further 500 will reinforce them, a French government spokeswoman said.
Constitutional battle
The unrest was triggered by a vote in the French parliament, 17,000 kilometres (10,600 miles) away, which on Tuesday said outsiders who moved to New Caledonia at least 10 years ago should be allowed to cast ballots in the territory's elections.
The reform must still be approved by a joint sitting of both houses of the French parliament.
Pro-independence forces say that would dilute the vote of Kanaks, who make up about 41 percent of the population.
Those favouring the reform argue voter lists have not been updated since 1998 -- depriving island residents who arrived after that date of the right to vote.
Macron has said French lawmakers will vote to adopt the constitutional change by the end of June unless New Caledonia's opposing sides agree on a new text that "takes into account the progress made and everyone's aspirations".
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)