Victoria Police has taken the extraordinary step of cancelling all fines issued by speed and red-light cameras hit by the "WannaCry' computer virus.

Acting Deputy Commissioner Ross Guenther made the announcement on Friday afternoon, saying about 55 cameras were affected by the the WannaCry ransomware virus between June 6 and June 22.

An investigation found the virus and had no impact on camera accuracy. Credit:Pat Scala

The cameras, most of them in inner-city Melbourne, issued 590 speed and red-light fines during that time.

Drivers will soon receive letters noting that those fines had been cancelled.