Ten earthquakes measuring more than magnitude 4.9 have been recorded in the Kermadec region north of New Zealand in the past 24 hours.
The largest was a magnitude 6.4 quake.
GeoNet said it has been monitoring what it calls an active sequence in the region.
The quakes have been largely unfelt and have not posed a threat to New Zealand.
It said the sequence was considered to be heightened activity for the region, and was not uncommon and did not mean there was a bigger quake coming.
"There is an active plate boundary in this region (extending up from the Hikurangi Subduction Zone in [New Zealand] up towards Tonga), that has the potential to cause earthquakes large enough to produce tsunami."
GeoNet warned large earthquakes could occur at any time in seismically-active zones.
GeoNet has been monitoring an active earthquake sequence in the Kermadec region north of New Zealand and has registered 10 quakes over M4.9 in the last 24 hours. The largest of these quakes was a M6.4. pic.twitter.com/PbiEqDtFtZ— GeoNet (@geonet) March 7, 2019