Geonet says the quake's epicentre was 50-kilometres north-west of Paraparaumu, at a depth of 48-kilometres.
Newstalk ZB caller Heather spoke to D'Arcy Waldegrave from Porirua, Wellington while the quake was still rumbling on.
She says it was a mighty shake - and her chair is still shaking underneath her.
Caller Eric lives about 15-minutes outside Palmerston North, and says the area was "hit with a biggie".
He says it started off with the house just shaking a little - and got bigger and bigger.
Civil Defence has advised there is no Tsunami threat.