The Ministry of Civil Defence is hailing the response to a tsunami threat as a success.
Civil Defence began warning of a potential tsunami about 3.45pm after a powerful earthquake magnitude 8 earthquake in the Solomon Islands earlier on Wednesday, but cancelled the warning at 9pm.
Emergency management director John Hamilton said he is satisfied with the public's response to its warnings and the response of regional Civil Defence groups.
However, he is concerned some people did not know about it, but said it is always a challenge to get the information out to everyone.
Mr Hamilton told Radio New Zealand's Morning Report programme he would look into why Northland was not included in the initial advisory.
He said there could still be some unusual waves on the western coast of New Zealand on Thursday, but nothing of any concern.
GNS Science seismologist Ken Gledhill says the Solomon Islands area is one of the most active in the world and the quake was no surprise.
In 2007, a quake killed at least 50 people and destroyed several villages.
Mr Gledhill told Morning Report that Wednesday's quake would have caused the same heavy shaking as people felt in Christchurch, and there have been a great many aftershocks.