Staff at the National Emergency Management Office - NEMO Tonga Photo: National Emergency Management Office - NEMO Tonga
A 7.3 magnitude earthquake struck Tonga just before midnight local time, 211km from the capital Nuku'alofa.
People in Tonga were initially evacuated to higher ground but so far there have been no reports of damages.
The Tongan government said the marine tsunami warning issued earlier for the entire kingdom has now been cancelled.
However, there are concerns for four fishermen who were at sea at the time the tsunami warning was issued.
The US Geological Survey said the quake was 24.8km deep, 211km from the capital Nuku'alofa and east of south-east of Neiafu.
An RNZ Pacific correspondent in Nuku'alofa said the quake lasted about two minutes.
In January, the Hunga Tonga-Hunga Ha'apai volcano eruption triggered a tsunami that destroyed villages and resorts and knocked out communications for the South Pacific nation of about 105,000 people. At least three people were killed.
Samoa and American Samoa on watch
In American Samoa, the National Weather Station issued a tsunami advisory.
It said some areas may have experienced strong shaking adding that its monitoring the situation
For Samoa, the meteorology office issued an advisory following a 6.5 quake earlier in the Fiji islands region.
"The depth is 38km and the distance is 560.34 km south west of the capital Apia," it said.
"The public is hereby advised that although there is a not tsunami from this earthquake please take extra precaution when you are attending activities near the coastal area," it said.