PORT VILA — A shallow 7.2 earthquake struck off Vanuatu Friday, seismologists said, sparking a tsunami warning which was later cancelled.

The quake at 04:14 am (1714 GMT Thursday) hit at a depth of 36 kilometres (22 miles), 214 kilometres northwest of Luganville, or 2,070 kilometres northeast of Brisbane, Australia, according to the US Geological Survey.

The United States issued a tsunami warning for areas of the South Pacific including the Solomon Islands, Vanuatu and New Caledonia.

Such warnings mean coastlines near the epicentre can be subject to tidal waves within minutes. But the alert was later cancelled.

An 5.7-magnitude aftershock hit ten minutes later 35 kilometres under the seabed, 190 kilometres northwest of Luganville, Vanuatu's second-largest city.

"Sea level readings do not show any tsunami signals," the Pacific Tsunami Warning Centre said.

"If a tsunami was generated it does not pose a threat to any areas outside the epicentral region. The tsunami warning is now canceled for all areas covered by this centre."

The centre had earlier called for authorities across the region to precautionary measures, saying: "An earthquake of this size has the potential to generate a destructive tsunami that can strike coastlines in the region near the epicentre within minutes to hours."