A hammer has been used in an armed robbery of a Bay of Plenty fish and chip shop.

Two men entered Ranolf Fish and Chips in Rotorua just before 9pm on Tuesday.

A police spokesperson says one of the offenders was armed with a hammer.

Police say the pair were acting in a threatening manner and demanded cash from the workers.

A cash box was taken with a small amount of money in it, along with one of the victim's cellphones, she said.

It's understood the pair fled the store on foot.

The offenders are described as Maori and in their early 20s.

Police say one had reportedly used a bandana to cover his face.

People with information about the robbery are asked to contact Rotorua Police Station on 07 349 9400.

Alternatively, information can be left anonymously via the Crimestoppers 0800 555 111 line.