A magnitude 4.3 earthquake was felt in Christchurch on Saturday night.
The tremor occurred at 11.27pm. It was centred 20km northeast of the city at a depth of 11km.
Police have had no reports of damage.
It was the strongest aftershock recorded since a magnitude 4.1 quake at 5.21am on Thursday, 20km north-east of the city and 15km deep.