Two more strong aftershocks hit Christchurch on Wednesday morning.
A magnitude 5.0 quake occurred at 6.27am, at a depth of 6km, 20km south east of Christchurch.
It was followed by a magnitude 4.2 quake at 6.32am, at a depth of 5km, also 20km south east of Christchurch.
Mayor Bob Parker says there is no report of any significant additional damage from the aftershocks.
There was a swarm of smaller quakes overnight. The largest was magnitude 4.0 at 9.41pm, at a depth of 10km, 20km south east of Christchurch.