The epicentre of the quake, recorded at 23:36 GMT on Monday, was 131km from Raoul
Island and at a depth of 35km.
A 6.0 magnitude earthquake struck the remote Kermadec islands north of New Zealand
on Tuesday.
There was no immediate alert from the Pacific Tsunami Warning Centre.
Earthquakes and volcanic activity are common in the area, which is part of the "Ring of
Fire" where the Pacific plate of the earth's crust meets other continental plates.
Two years ago, a conservation worker was killed on Raoul Island when caught in a
mudflow after a volcano erupted during an earthquake swarm.
In the past two months, tremors of 7.3, 6.5 and 6.0 have been recorded in the area,
1 000km north of New Zealand.