A tropical cyclone hit part of New Caledonia on Friday, damaging buildings and uprooting trees as it barrelled towards the capital of the South Pacific island territory.

Meteorologists said Cyclone Vania, packing winds of 100 kilometres (60 miles) an hour and gusting up to 150 kilometres an hour, was 50 kilometres north of Noumea as night fell.

Authorities issued their highest level warning for Noumea and southern areas, urging people to stay indoors.

Emergency shelters were opened in the capital to provide temporary accommodation for people from slums on the outskirts of the city and 600 people sought refuge from the storm.

Vania has caused serious damage on the Loyalty Islands, which form part of the French-governed territory.

"A lot of trees have been pulled up and roads flooded but it is too soon to give an assessment of the situation in Noumea, which is currently affected by Vania," French high commissioner Albert Dupuy told AFP.

After hitting the island of Lifou overnight, Vania moved southwest unexpectedly and is likely to leave New Caledonia on Saturday, according to Meteo France.

The Loyalty Islands were hit by a 7.3-magnitude earthquake in the early hours of Friday morning, prompting residents to flee in fear of a tsunami, a local official told AFP.

A 10-year-old boy died on Lifou because of a heart problem while fleeing his house with his parents, local sources and Dupuy said.