A magnitude 4.3 earthquake jolted many Christchurch residents awake this morning.
The quake at 3.32am was centred near Cashmere and was at a depth of 5km.
GeoNet listed the quake as strong, and more than 1800 people reported feeling the tremor from as far south as Dunedin and Gore.
RNZ listeners texted that it was a "short, very sharp and loud" quake and "really, really rocked the place".
It was followed by a number of aftershocks, the biggest a magnitude 3.0 shake at 6.14am, and five smaller tremors, the latest at 7am.
St Martin's resident Greg Jackson was woken by the shaking.
"Everything's as quake-proofed as it can get, but our house is fairly close to toast. It's habitable, but all you do is wander out and make sure it's still attached to the piles and see how much more has fallen off the rubble foundations."
Last Monday, the city marked five years since the 22 February 2011 earthquake that left 185 people dead and Christchurch devastated.
Mr Jackson said people were are feeling very stressed after the earthquake two weeks ago and the continuing aftershocks.
There have been no reports of damage to homes or any injuries following today's quake.
Just heard another rumble... I want sleep!! Monday's are bad enough .. Add in quakes and little sleep... Bad combo #eqnz— Cinder Ella (@AutumnMoonRain) February 28, 2016
Not looking like sleep will come soon. Early cuppa and a book. #eqnz— David Woodings (@MargeInovera) February 28, 2016
Nothing like an earthquake to get you out of bed early. Going to be a long day. #eqnz— Kirsty Collett (@kirstycollettnz) February 28, 2016
GNS seismologist Caroline Holden said this morning's shaking was extreme for the size of earthquake.
"We recorded about 10 times less than for the February earthquake, which is still very, very high for such a small magnitude earthquake.
"So definitely a good jolt.
"The Canterbury earthquakes have this characterisation of being rather punchy earthquakes," she told Morning Report.
"This latest one is proving this again."
It was difficult to tell whether whether this morning's tremors were related to the February 2011 sequence of aftershocks or the Valentine's Day quake, but it was "definitely nothing unusual."