Watch: Dramatic moment robber plunders Blenheim dairy at knifepoint

Frightening security camera footage has been released showing the moment a man pulls a large kitchen knife on a shopkeeper before wrenching a till off the counter.

Marlborough Police are appealing for help to identify the man, posting the terrifying 31 seconds on Facebook when a dairy owner comes face-to-face with an armed man.

The man, his head disguised by a hoodie pulled tightly around his face, is shown calmly walking into the Maxwell Rd dairy in Blenheim before reaching into his backpack and pulling out a knife.

Brandishing the fierce-looking carving knife in the direction of the hapless female shopkeeper he motions to open the till.

She is shown backing away from the counter.

At this point the robber reaches over and attempts to open it. When the drawer fails to budge he lifts up the till, wrenching it out of the socket before disappearing on foot out of the shop.

Police said while they were awaiting forensic results from the hold-up that happened on December 29 they were releasing footage of the daytime theft to try to capture the robber.

Anyone with information was asked to contact Blenheim Police on (03) 578 5279 or anonymously on 0800 555 111.