Tau entered the dairy about 6.55pm on June 17 but left after spending less than 30 seconds inside.
A short time later, he re-entered carrying a plastic bag and placed a carton of juice on the counter. Tau then told the dairy owner he had to get his wallet and left the store. Within a minute, he came back and handed the victim a $5 note.
He was given $1.50 change which he used to purchase a bag of confectionary worth $1.
Tau then reached into the plastic bag and pulled a hammer. He lifted the weapon up to the height of his head and said to the dairy owner: "Give me all the money."
The victim attempted to push his hand away but Tau switched the hammer to his left hand and pulled the till towards him. He opened the till and removed $270 in notes before running away.
Crown prosecutor Jarred Scott said the offending was premeditated and a hammer was used to threaten the dairy owner. He said the dairy owner's wife was receiving counselling and the business has had to incur an additional cost of having two staff on duty after the robbery.
A sentence of home detention, he submitted, was inappropriate.
Tau's lawyer Arthur Fairley said home detention was never and could not be advanced. He highlighted Tau's early guilty plea and remorse and an apology letter he wrote to his victim. Mr Fairley said Tau was at a medium risk of re-offending and had a strong and positive relationship with his whanau.
Judge Harvey fixed a starting point of four years before reducing it by one year for mitigating circumstances, including the early guilty plea.
