Sharp quake hits in NZ's South Island

An earthquake measuring 4.5 has shaken much of New Zealand's Canterbury region.

Canterbury residents have received an unwanted early morning wake-up call from a sharp earthquake.

The quake, which had a magnitude of 4.5, struck at 2.37am local time at a location 25km southwest of Christchurch at a depth of 9km.

The earthquake was felt as far away as Blenheim.

Media reports suggested it was bigger than many in the region had felt for a while and some social media users described it as "strong and loud".