A Porirua dairy attendant was subject to an aggravated robbery on the night of Sunday, May 31.
The lone male shop assistant was held up with a long- barrelled firearm by a male offender who demanded cash, police inspector Marc Clausen said.
The incident happened just after 7.30pm at the Corinna St dairy in Waitangirua.
A small amount of cash was taken. The offender was described as wearing black clothing and had his head covered.
Police are asking for anyone with information, or anyone in the area who saw suspicious behaviour, to contact Porirua police on 238 1400 or the anonymous Crimestoppers line on 0800 555 111.