Some buildings in Wellington were evacuated, and items were knocked off shelves in places. Police were trying to verify reports that one house near the quake's centrer was severely damaged.
There were no initial reports of injuries.
The magnitude 6.8 quake struck just after 2:30 p.M. Near the South Island town of Seddon, followed by a series of smaller aftershocks.
Boulders fell onto State Highway 1, the major route for traffic near Seddon, said police spokeswoman Barbara Dunn. She said she was trying to verify reports that one home in Seddon had been severely damaged.