He was wearing blue pants, a black hoodie and white shoes.
Indications suggest the male attempted to get into the till, she said.
Officers have returned to the shop todayfor further forensic examination.
The incident comes as police appeal for sightings of another attempted aggravated robbery in the Bay of Plenty.
About 5.35pm on Friday, a man entered the Allandale Superette in Whakatane with a large knife and demanded money.
Again, the shop assistant was not harmed and the man left empty-handed. The offender was described as of medium height, stocky build and about 30 years old. He wore a blue hoodie and light-coloured pants.
The spokeswoman said the incidents did not appear to be linked.
People with information on either incident are asked to contact their local police station or call Crimestoppers anonymously on 0800 555 111.