An 6.3 magnitude earthquake has hit New Zealand’s South Island, hours after an initial quake killed two people.

The new tremor struck at a depth of 10km, Northeast of Christchurch.

A 7.5-magnitude quake, with the same depth, had hit the same area just after midnight, triggering tsunami warnings.

Meanwhile, residents around the Clarence river – one of the largest on south island  have been urged to leave the area.