Quake strikes off Tonga

A 6.3-magnitude earthquake has struck off the coast of the Pacific Island nation of Tonga but experts say there is no threat of a tsunami.

The quake reportedly struck in waters northeast of the Tongan capital, Nuku'alofa, at about 7pm local time on Saturday.

Geoscience Australia reports the impact could have been felt by people more than 600-kilometres away.

Seismologist Marco Maldoni said residents of the island nation would definitely felt shaking after the movement of tectonic plates and that that part of the world was prone to earthquakes.

"That earthquake itself happened where the Australian plate meets the Pacific plate," Dr Maldoni told AAP on Saturday.

"Thankfully this is a non-tsunamigenic earthquake - something that can potentially generate a tsunami."

Dr Maldoni said that in the past five years there had been about 200 earthquakes within that area, with another one occurring near Tonga at a magnitude of 6.2 as recently as Friday.