Cyclone Jim, which is northwest of New Caledonia, and west of Vanuatu, is expected to bring powerful winds and widespread rain to the region over the next 24 hours.
Jim is forecast to increase in intensity with winds at its centre rising to 85 knots or around 150 kilometres an hour as it heads in a generally southeasterly direction.
This will take it to the north of New Caledonia's main island but some smaller islands are in its direct path.
The Vanuatu Met service says it does not yet pose any direct threat to Vanuatu.
However it warns there will be heavy rainfall over the central and southern islands tomorrow.
It warns this could cause rivers over some areas to overflow their banks and or flooding of low lying and flood plain areas.
Seas are expected to become rough to very rough tonight, with heavy swells developing.
In New Caledonia, the French High Commission has issued a cyclone alert for north of the main island, from a line north from Kone on the west coast to Poindimie on the east.
The alert also applies to the Loyalty islands.