Canterbury has been struck by an earthquake 4.1 in magnitude.
It struck at 12.24pm and was centred 10km west of Christchurch at a depth of 16km, Geonet reported.
Several Christchurch residents reported feeling buildings shake.
Adrienne Rewi tweeted: "Enormous earthquake in Christchurch... whole building shaking...it's been a while! #eqnz"
Juliet Speedy said: "5 year old: 'I've never felt one of those before Mum. Are we going to die?' #eqnz #betterquestions"
Ashley Campbell: "I am proud of the fact I have taught my animals not to react. Not a peep out of @CuteHettie at that 4.2 #EQNZ"
St John Ambulance says it has had no reports of injury from the quake.
"This earthquake is a reminder that we are still in the post-earthquake period in Christchurch and Canterbury," said Ian Henderson, St John communications adviser for the South Island region.
"We strongly encourage people to keep an eye out for their friends and family, especially those who are ill, live alone or who are frail.
"This is especially important as we head towards the fifth anniversary of the February 22, 2011 earthquake and earthquakes will be on peoples' minds."
A second magnitude 3.0 quake was recorded 22 minutes later, at 12.46pm, 15km northwest of Akaroa.
However, it appears if there's any damage it is only minor as the Fire Service has not been sent to any calls since the two earthquakes.
A Southern Fire Communications spokesman said they felt it but had not received any calls for help.