An earthquake of 5.8 magnitude struck near the New Zealand city of Christchurch on Friday, New Zealand's civil defence said, prompting the evacuation of some public buildings and sending goods toppling from shelves.
Christchurch, the largest city in New Zealand's South Island, is recovering from a quake measuring 6.3 which killed 182 people in February and caused up to NZ$20 billion (9.9 billion pounds) in damage.
Christchurch police said there were no reports of casualties or widespread damage, although one person had been reported hurt at a shopping mall and taken to hospital.
The quake was centred 20 km (12 miles) northeast of the city at a very shallow depth of 8 km (5 miles) and struck as shoppers thronged malls in the lead-up to Christmas.
It was incredibly violent, one caller told Radio New Zealand.
All the water in my birdbath slopped out and I could hear everything falling over inside. When I walked inside, the cat streaked out the door, ornaments were all over the floor, contents of the pantry were lying on the floor, a little bit of smashed glass and picture frames lying over.
Radio New Zealand said malls and office blocks had been evacuated after goods were toppled from shelves and some ground liquefaction and rockfalls had also been reported.
The region's main power supplier said up to 15,000 customers were without power, mostly after circuit breakers were tripped.
Christchurch International Airport was evacuated as a precautionary measure while the terminal and runways were checked.
We're confident we will be running again this afternoon but we need to go through our checking procedures first, an airport spokeswoman said.
The New Zealand dollar briefly dipped to $0.7725 from $0.7740 in thin trading after news of the quake, before recovering. New Zealand stocks cut pared gains to trade up 0.14 percent.
New Zealand straddles the boundaries of the Indo-Australian and the Pacific tectonic plates and is hit by about 14,000 quakes every year, of which only a small number usually top a magnitude of 5.
Large areas of Christchurch's central business district are still off-limits after the February quake, which toppled the city's famous cathedral, as well as shops, homes and office buildings.
A quake of lesser intensity struck Christchurch in September last year.
Scientists had warned after the February quake that there would be further shakes, probably as large as magnitude 6.
In coming days the most likely scenario is that there'll be a series of after shocks in a similar location and they'll gradually drop off, Ken Gledhill a seismologist with GNS Science told TVNZ.
This is just a reminder that this area is more active than it was in September 2010.
($1 = 1.2914 New Zealand dollars)
(Reporting by Lincoln Feast and Gyles Beckford)