A 4.8 magnitude earthquake has rattled Christchurch.
Geonet said the shock hit at a depth of 11 kilometres, about 20 kilometres southeast of Darfield, just before 3:30pm.
St John has had no reports of injuries following this afternoon's earthquake.
Its epicentre was near the town of Rolleston.
A Geonet seismologist said early calculations put the quake at 5.0, but those had since been downgraded.
The quake was followed by a magnitude 3.1 aftershock at a depth of eight kilometres about 25 km west of Christchurch at 3:41pm.
Christchurch residents took to Twitter to report the latest shock, with some describing it as "huge".
EmmaJayJenkins said: "Crazy earthquake made my car start bouncing around while we were waiting at the lights!"
RepsTweets said: "I'm still shaking, that was huge."
Newstalk ZB reporter Brian Ashby said it felt like a long, rolling one.
"I heard it coming, I was wondering if it was traffic, a big truck. All of a sudden then it hit, and it rolled. It probably lasted about 20 seconds.''
A magnitude 4 quake hit the city last Friday.