Sgt Ealson was referring to one recent incident at the Queenstown McDonald's that resulted in the restaurant's duty manager being sentenced last week to seven months' home detention.
Rishi Kumar (34) was convicted of injuring with intent to cause injury after he grabbed a customer, swung him around, punched him to the ground and stood on his torso and kicked the man in the head.
Kumar has since said he was under pressure that evening and his victim was intoxicated, yelling racial abuse and spat on him.
Last week, Kumar claimed his requests to his employer, Mark Julian, for more security were not acted upon. He had been removed from his managerial position after the August 30 incident.
Sgt Ealson said Queenstown police were working with McDonald's management and other outlets notorious for police callouts for drunken behaviour.
"Unfortunately, McDonald's has been in the press recently and we are working with establishments on security issues."
Sgt Ealson said the installation of the CCTV system had assisted police in identifying people and establish what had occurred.