Earthquakes have shaken central New Zealand and Canterbury early on Thursday.
A 4.9 magnitude tremor at 12.56am was centred in Cook Strait, 25km south-east of Seddon. It was 22 kilometres deep. The quake was felt throughout central New Zealand.
Another tremor, of 4.5 magnitude, hit the same area at 6.38am and was at a depth of 25 kilometres.
GNS Science estimates more than 2100 aftershocks have occurred since the 6.5 magnitude Cook Strait earthquake on 21 July.