Two robbers lay in wait for a Chartwell Burger King worker to put out the rubbish before pointing a sawn-off shotgun at his head and marching the man back inside.
The thieves had meticulously planned the late-night robbery, waiting for staff to close the fast food restaurant in Hamilton before making the ambush.
Hamilton CIB detective Will Loughrin said the duo, who made off with an undisclosed sum of money following the aggravated robbery last Wednesday, put lives at risk and he is calling on members of the public to help catch the offenders.
"We believe the two men involved had familiarised themselves with the layout of the premises before they struck, laying in wait for a staff member to take out the rubbish after closing, about 11.25pm."
One of the men put the sawn-off shotgun to the head of the worker and forced him back into the store where they confronted three other staff members including the supervisor before stealing the money.
Police are hoping people will notice the distinctive wrapping paper used to hold the coins taken.
"We are particularly interested in hearing from anyone who has seen or been offered rolls of 50c and 20c coins wrapped in white and orange and white and black, 'ACM' marked paper," Mr Loughrin said.
"In addition we want to hear from anyone who comes across abandoned wrapping of this nature or clear plastic bags marked 'change bags'."
Mr Loughrin said it was concerning the robbers had pointed a gun at staff and said the premeditated planning suggested a familiarity with the area.
He said now that a week had passed since the robbery, police were concerned the offenders might feel confident enough to strike again unless they were caught.
The Burger King staff were now back at work but Mr Loughrin said the incident had shaken them.
The offenders were both described as being Maori or Pacific Islanders and about 168cm tall.
One was of stocky build with brown eyes and wearing a black woollen scarf around his face, a black beanie and a black hooded sweatshirt, pants and puffy black jacket.
The second offender was also stocky and wearing a black hooded sweatshirt and tan pants.
* Anyone with any information is asked to contact Mr Loughrin on 027-7048-589.
Alternatively information can be left anonymously with Crimestoppers on 0800-555-111.