Christchurch has been shaken by a magnitude 4 aftershock today. 

The quake struck at 11.07pm and was centred 10km southwest of Christchurch at a depth of 12km. 

Social media users described the shake as "sneaky", "agressive" and "a cheeky little number".

There were no reports of damage or injury.

A 3.0 was in the same location 59 minutes later