The initial tremor struck at 4:37am on Friday, centred 130km off Te Araroa. It was 55km deep, according to quake monitoring service GeoNet.There are no reports of damage or injuries yet, but items were knocked off supermarket shelves.
Civil Defence warned people to stay away from beaches, saying there was potential tsunami threat. The threat was called off at about 8:30am.The first tsunami waves arrived on the East Cape at about 6am, measuring 30cm high.
Auckland Transport warned train commuters to expect widespread delays and cancellations as a result of the quake. Kiwirail closed the line between Newmarket and Britomart for a couple of hours this morning as a precautionary measure because part of the line runs below sea level.
It could also be felt in Auckland, Northland, Palmerston North, Napier and even Blenheim and Christchurch in the South Island.
Expect aftershocks and remember to drop, cover and hold.
Look after yourself and get first aid if necessary. Help others if you can.
Assess your home or workplace for damage. If the building appears unsafe get everyone out. Use the stairs, not an elevator and when outside, watch out for fallen power lines or broken gas lines. Stay out of damaged areas.
Look for and extinguish small fires if it is safe to do so. Fire is a significant hazard following earthquakes.
Listen to the radio for updated emergency information and instructions.Do not overload phone lines with non-emergency calls.
Help people who require special assistance – infants, elderly people, those without transportation, families who may need additional help, people with disabilities and the people who care for them.
Friday's quake follows a 5.7 tremor that shook the same area yesterday.