Wellington has been rocked by a severe magnitude 6.5 earthquake this afternoon.
GNS said the quake at 2.31pm, which was only 17km deep, was centred 5km east of Seddon, which is close to the epicentre of last month's big shakes.
Reports are coming in that the quake was felt widely across the North Island, including Tauranga.
@RiseUpNZ tweeted "Did you feel that quake? Felt here in the Tauranga avenues - swaying for about 30 seconds".
@sjknz tweeted: "Lights have been swinging up here in Tauranga. Really feel for you in Wellington #EQNZ".
There were also reports of a house collapsing in Nelson after the quake.
Wellington had also lost cellphone coverage.
Ambulance central communications said they had yet to receive any calls related to the earthquake.
TranzMetro said it had immediately stopped all train services in the capital.
Wellington's railway station had been evacuated.
No tsunami threat has been issued.