A youth armed with an axe threatened a staff member at Victoria Food Market in an aggravated robbery on Monday morning.
Manager Lucas Guo said the shop had not long been open when a young male wielding an axe entered the store where he was working alone.
"He came in holding up the axe and told me to put money in his bag," Guo said.
"He kept waving the axe around. I gave him $19 and then he ran away.
"It was very scary. We haven't had anything like that in this shop before."
Guo was not injured but was shaken by the incident.
A police spokeswoman said police were called to the Victoria Ave store, between Caltex and KFC, at 8.35am on Monday.
Police found a 14-year-old youth nearby at about 9.30am and he was helping police with inquiries.
There have been at least 18 other armed robberies and ram raids in Whanganui since December 2016, with offenders arrested and prosecuted in connection with seven.