Manawatu Countdown supermarkets are reviewing their security measures after three stores were targeted within a week by armed robbers.
In the latest incident a disguised man, armed with a hammer robbed a Feilding store of cash about 9.45pm yesterday.
He was wearing a plain blue hoodie over his head and a scarf or bandana across his face.
After the robbery, the man fled towards Bailey and Denbigh streets, acting Detective Senior Sergeant David Thompson said.
"No one was hurt during the robbery but staff members were clearly shaken with what had occurred."
The man was described as light skinned, thin build and about 180cm tall.
"This robbery is now the third that has occurred in the last few days where Countdown supermarkets have been targeted," Mr Thompson said.
Countdown is reviewing security at their stores and is increasing security as a result of these recent robberies.
Detective Shane Brown of Feilding police said on Sunday a person attempted to rob a Palmerston North Countdown with an "edged weapon" like a knife, but ran from the scene after being confronted by a security guard.
"And then they went straight to the next one in Palmerston North and they had the same weapon with them, and they were successful with that (robbery), he said.
Police want to speak with anyone who was in the Feilding Countdown last night and who may have seen the robber run from the scene.