Speed camera operators in Victoria will walk off the job for 24 hours as they step up their fight for better pay and conditions.
The Community and Public Sector Union expects up to 200 members working for Serco to go on strike, which they say is more than half the workforce.
The industrial action begins at 12.01am on Wednesday and a protest is planned outside Serco's offices in Tullamarine during the afternoon.
A spokesperson for the union said the operators earn $26 an hour and face safety issues such as being attacked in their cars, vehicles swerving at them, verbal abuse and social media harassment.
"It's well past time for the state Government to review Serco's performance and consider alternatives for the delivery of this important road safety service and protect these government contracted workers," they said.
Serco said it respects the right of union members to take part in protected action and has sought assistance from the Fair Work Commission to resolve the situation.
"Mobile road safety cameras will still be operating over the next 24 hours and are there to ensure the safety of the community," a spokesperson said.
"As per previous stoppages we expect little impact on our operations."
The Victorian Government said the industrial action was a matter for Serco and unions.
"We expect Serco and their staff to continue to engage in good faith and that any protected action does not endanger community safety," a statement read.
"We will monitor the impact of any industrial action as the parties work towards reaching a resolution."
