An earthquake measuring 7.6 on the Richter scale jolted the Kermadec Islands region of New Zealand at 1903 GMT on Wednesday (07:03 New Zealand local time on Thursday), the U.S. Geological Survey said.
The quake was centered 161 km east of Raoul Island of the Kermadec Islands, which is some 920 km south of Tonga. The epicenter was at a depth of 20 km.
No damages have been reported so far.
The U.S. Pacific Tsunami Warning Center has issued a non- expanding regional tsunami warning for the Kermadec Islands, New Zealand and the Pacific nation of Tonga.
"This tsunami may have been destructive along coastlines of the region near the earthquake epicenter. Authorities in the region should take appropriate action in response to this possibility," the Center said in a statement.
New Zealand's Civil Defense has issued a tsunami warning for New Zealand's Northland, Bay of Plenty, East Coast and Hawkes Bay.
The National Crisis Management Center has been activated and Civil Defense said the first wave to arrive will reach New Zealand at 8.52 a.m. on Thursday.
Civil Defense said people in coastal areas should stay off the beaches, stay out of the water and not go sightseeing.
A wave of between 60 cm and 1 meter have been detected at Raoul Island.
Civil Defense said it is not expecting a wall of water but is concerned about strong currents in coastal areas.
East Cape will be the first place to see the wave at about 8.52 a.m., North Cape at 8.54 a.m. and Gisborne at 8.59 a.m. It is expected to arrive in Auckland at about 10 a.m.
The first wave may not be the largest. Waves will continue for several hours.
The Kermadec Islands, which are often rocked by severe quakes, have no permanent population. Only a small New Zealand Department of Conservation team live on Raoul island.