Senior Sergeant Dale Johnson said police would be testing cars to check whether their window tint was impeding the driver's vision and complied with Victorian road laws.

"We've detected far too many vehicles with tints as low as 3 per cent. The legal tint is 35 per cent or higher," he said.

"If you're getting your windows tinted, make sure to ask the light transmittance percentage and if you doubt the legality of your tint, get it checked."

According to VicRoads, windscreens fitted to cars manufactured before July 1971 must transmit at least 70 per cent of visible light. All other cars must have light transmittance of at least 75 per cent.

All windows other than the windscreen must have light transmittance of at least 35 per cent. Any car that does not comply is not roadworthy.

"Drivers need to realise this is extremely dangerous," Sergeant Johnson said. "By not being able to see into a vehicle, eye contact can't be made with drivers and the visibility from the vehicle is dramatically impeded."

The police operation, called Operation Halo, will run until the end of the year and will also focus on other areas of road safety including speeding, drink and drug driving, traffic sign and signal compliance, and safety equipment for bikes.

Police will converge on high-traffic areas used where pedestrians, cars and bikes converge, such as near sporting areas and popular tourist destinations.

The operation will run in the cities of Melbourne, Yarra, Glen Eira, Bayside, Moreland and Port Phillip.