Christchurch was shaken by two earthquakes early on Wednesday morning.
The first, at 3.17am on Wednesday measured 4.0 and was centred 20 km east of Christchurch at a depth of 8 km.
The second 3.3-magnitude quake occurred at 3.40am, was centred 20 km west of the city and was at a depth of 2 km.
There have been no reports of damage.