French forces launched a "major operation" on Sunday to regain control of a road linking New Caledonia's capital Noumea to the main international airport, after a sixth night of violent unrest.
Officials said more than 600 heavily armed gendarmes were dispatched to secure Route Territoriale 1, the main artery connecting the restive capital with air links to the outside world.
Six people have been killed and hundreds injured since rioting began on Monday, according to local authorities.
The violence has been fuelled by economic malaise, ethnic tensions and long-standing opposition to French rule on the Pacific archipelago.
A nighttime curfew, state of emergency, ban on TikTok and arrival of hundreds of troops from mainland France failed to prevent more unrest overnight Saturday to Sunday.
Unidentified groups set two fires and raided a petrol station, according to the office of New Caledonia's high commissioner.
But authorities insisted the situation is improving.
"The night has been calmer," the commissioner's office said.
Local media reported a public library was among the buildings burned.
The mayor's office told French press agency AFP there was "no way of confirming for the moment" as the "neighbourhood remains inaccessible".
Trapped tourists
For almost a week, protesters have set vehicles, shops, industrial sites and public buildings alight, while pro-independence forces have blocked access to Tontouta International Airport.
A local business group estimated the damage, concentrated around Noumea, at more than €200 million.
AFP reporters attempted to reach the airport on Sunday but were stopped by groups blocking access at several locations.
Flights to and from New Caledonia's main island have been cancelled since the unrest began, stranding an estimated 3,200 travellers and cutting off the trade route.
Australia and New Zealand are among the nations waiting for Paris' all clear to send planes to evacuate trapped tourists.
In Wellington, Foreign Minister Winston Peters said on Sunday that the New Zealand Defence Forces had "completed preparations" for flights to "bring home New Zealanders in New Caledonia while commercial services are not operating."
(With newswires)
