People in New Caledonia's very north are being urged to stay inside until tomorrow morning as Cyclone Sandra passes to the territory's west.
A red alert applies to Belep and the northern tip of the main island.
A duty forecaster at the Fiji Meteorological Service says the storm is moving south-south-east at just over 11 kilometres an hour.
Amit Singh says Cyclone Sandra's most destructive winds are not likely to affect land areas.
"You can expect some damage to vegetation and some trees which are not that strong, like the banana tree and the paw paw tree, they may be damaged. Not much damage to houses which are built strongly but temporary sheds, they may get blown off by gale force winds."
Amit Singh says forecasters are confident Cyclone Sandra will maintain its direction and weaken to a low pressure system by Thursday.