A shop owner hit an armed robber over the head with a mop and chased him down the road during one of four aggravated robberies in the Rotorua area in five days.
Police say there are concerned by the spate of recent incidents, and it was fortunate no-one was injured.
On Sunday at about 7pm a man in a balaclava entered the Koutu Rd Four Square store armed with a 30 centimetre kitchen knife.
"The offender removed a till, however, before leaving the shop he was confronted by the shop owner who struck the robber across the head with a mop, forcing the offender to leave empty-handed," said Detective Sergeant George Staunton.
The shop owner gave chase for about 100 metres before losing sight of the man, who was described as being of fat build, around 178cm tall, wearing a blue hoodie with a grey diamond-patterned sweatshirt over the top.