"I would expect they got less than $20 worth of goods, but they have committed a crime that could see them end up in jail for a very long time.
"This is huge-risk, high-stake offending for very, very little reward, and that's where the thoughtlessness and stupidity of their actions lie."
Aggravated robbery carried a maximum sentence of 14 years' imprisonment.
Meanwhile, Mr Beatson is appealing to anyone who saw the robbers before, during or after the incident to make contact with him or Detective Richard Garton, who is leading the investigation, at the Kaitaia police station, phone (09) 408-6500.
Any suspicious activity in the Plaza Lane, Te Reinga Street, Pukepoto Road and Puckey Avenue areas should also be reported.
Other similar business owners in the Kaitaia area had been contacted by the police and told of the incident, and they were ready and prepared for the worst, he added. The police had also stepped up patrols in their locations.
"With shop owners being forewarned, they have beefed up security measures and are keeping little of value on-site," he said.
"Robbers will find they have very little to gain but a lot to lose."