Nearly 5000 people have reported feeling a shallow earthquake centred in Christchurch, at about 11.50pm yesterday.
The Geonet site shows the quake registered at a magnitude of 3.5, but with a depth of just 6km.
Of the 4800 or so 'felt it' reports collected by the website, 11 have described the shaking as 'extreme' - the strongest rating possible.
Three of those were in Nelson, the rest in Christchurch.
And the quake was felt as far away as Auckland and Invercargill, although the shaking in those centres was described as 'light'.
Fire and Emergency says no damage has been reported.