Christchurch police want help with information after the third aggravated robbery in just over a month at the same Night'n Day store.

Three masked offenders armed with weapons robbed the shop in Woolston at 4.20 this morning, making off with cash and cigarettes.

One of the offenders was wearing a red hoodie and another was wearing a black one.

Police are keen to hear from anyone who saw anything suspicious in the area at the time, or who recognises anyone in the CCTV still image to contact Christchurch Police on 03 363 7400.

Alternatively, information can be provided anonymously on 0800 555 111.