+ A magnitude 6.3 earthquake rocks Christchurch on February 22 at 12.51pm local time (10.51am AEDT).

+ GNS Science said the quake struck 20 kilometres south-east of Christchurch, at a depth of five kilometres.

+ Police have confirmed there have been "multiple fatalities".

+ Christchurch mayor Bob Parker says several people in the city council building had been injured.

+ The national crisis management centre has been activated.