New Zealand's quake-ravaged Christchurch city was struck by a strong earthquake causing further damage after a strong quake hit the city last year, local media reported on Tuesday.
The quake was measured at magnitude 6.3 by local scientists with a focal depth of 5 kilometres, 10 kilometres southwest of the country's second biggest city.
Local media reported filing cabinets and computers being thrown from desks, damage to buildings, and a city bridge made impassable.
The city was struck by a force 7.1 quake last September which caused widespread serious damage but only minor injuries.
The region has been struck by thousands of aftershocks since the original quake.
There were reports of further debris falling from already damaged buildings and people were evacuated from some offices in the central business district as checks were made.
New Zealand, which sits between the Pacific and Indo-Australian tectonic plates, records on average more than 14,000 earthquakes a year, of which about 20 would normally top magnitude 5.0.