Building engineers will be out in force today checking structures in the capital, and around the South Island for safety.

LISTEN ABOVE: Gerry Brownlee speaks to Mike Hosking

Acting Civil Defence Minister Gerry Brownlee said a number of buildings will need to be assessed, before people can go inside.

"I understand the Wellington City Council have been advising people that they should stay away from CBD buildings for a time this morning to ensure that those buildings are inspected and declared safe."

Gerry Brownlee has been at the Civil Defence emergency bunker in Wellington.

He described the quake as frightening and violent.

"It went on for quite some time and was of a reasonably violent nature."

"When people describe it as rolling, that's one way to think of it but it was significant movement."