Small tsunami waves lapped New Caledonia, Fiji and Vanuatu Wednesday after a strong earthquake in the Pacific Ocean, but the threat passed without any damage reported.

After the 7.1 magnitude quake struck off the eastern coast of New Caledonia, the Pacific Tsunami Warning Center said "waves reaching 0.3 to 1 metre above the tide level" were possible.

But only minor sea level fluctuations were recorded and the warning was soon called off.

Despite this coastal populations were urged to "stay alert" and follow instructions from local authorities.

The tremor hit at a depth of 27 kilometres (17 miles) in the southern Pacific Ocean, some 231 kilometres from the nearest town, Tadine, in the lightly-populated Loyalty Islands, the US Geological Survey said.

Geoscience Australia said shaking would have been felt throughout New Caledonia, but it put the damage radius at 103 kilometres -- well away from land.

Jonathan Hanson, duty seismologist at New Zealand's GNS Science, said the epicentre was some distance from inhabited islands and the tsunami wave warnings were modest.

"The tsunami wave sizes we've seen reported are 16-17 centimetres (6.3-6.7 inches) at two New Caledonia stations. At those sizes we wouldn't expect any damage," he told AFP.

New Caledonia's Civil Security department said there was no risk of major flooding.

"Given its location, depth and magnitude, abnormal changes in sea levels could be seen in the Loyalty Islands," it said.

"Since there is no risk of major flooding along the coast, no action by the public is required," it added, calling nonetheless for coastal residents to exercise "caution".

Fiji's disaster management minister tweeted that the quake "does NOT pose any immediate threat to the Fiji region".

New Caledonia, a French overseas territory, Fiji and Vanuatu are located within the "Ring of Fire", a zone of tectonic activity around the Pacific that is subject to frequent earthquakes and volcanic eruptions.