Christchurch has been shaken by a 4.2-magnitude earthquake, hours after a smaller one hit the region.
The tremor was recorded 20km west of Christchurch, at a depth of 12km, at about 3.30pm (1330 AEDT) on Friday.
GeoNet listed its intensity as moderate and more than 650 people reported that they had felt the shake within minutes.
The quake followed a smaller, 3.2-magnitude tremor in the same area at about 1.10pm.
That quake also had a depth of 12km and was described as of light intensity by GeoNet.