Christchurch police are appealing for any information about an armed robbery at a supermarket late on Saturday night.

Three men took money from a cash register at the Countdown in Northlands Mall, then assaulted a security guard with a metal pole, similar to a crowbar, as they left.

The robbery happened at about 11.20pm and left the security guard with a minor injury.

Police have released photos of the offenders, who disguised their appearance with dark coloured hoodies and gloves and wore balaclavas over their faces.

Photo: Supplied / NZ police

Anyone with any information that could help to identify the offenders should contact Christchurch police or Crimestoppers (0800 555 111).