A magnitude 7.4 quake has occurred off the coast of Tonga.
The US Geological Survey said it was centred almost 270km southwest of the capital, Nuku'alofa.
It said the quake was recorded at a depth of 160km.
No tsunami warning was issued.
Police Commissioner Grant O'Fee said that while the shake was strong, he has received no reports of injuries or damage.
Geonet said two shallow quakes recorded off the East Coast of New Zealand - of magnitudes 5.6 and 6.1 - were falsely reported by its automatic computer system reacting to waves from the Tonga quake.