NSW Police spent more than $2 million on semi-automatic rifles that have never been fired at a crime or during a police operation.

In June 2017, NSW Police commissioner Mick Fuller announced a multi-million-dollar plan for Colt M4 carbine semi-automatic rifles to go to about 100 Public Order and Riot Squad officers to patrol the 2017 New Year's Eve crowds with fears of terrorism behind the change.

NSW riot squad police officers with military-style machine guns rolled out in December 2017. Credit:Ben Rushton

Since then military-style machine guns have cost taxpayers more than $2 million with the cost of ammunition hitting $574,138, a freedom of information request by the Herald reveals.

Associate Professor of Criminology at Bond University, Dr Terry Goldsworthy, questioned why police need military weapons, adding his research found "very seldom" cases where police were outgunned.