Naked man gyrates in front of speed camera

A speed camera operator was forced to lock himself in his car while a naked man rubbed his body on the windows.

The aggressive and abusive man also waved his genitals at passing cars during two altercations with the same speed camera operator in Rowville on Australia Day, police say.

They have released CCTV footage in the hope of identifying the man, believed to be in his 30s.

Constable Charles Ryall said the camera operator sounded an alarm to scare the man off, but he instead carried on for up to 10 minutes.

He returned again with alcohol an hour later and exposed himself again.

"He rubbed his genitals around the front of the car near the passenger side window where the operator was sitting," Constable Ryall told AAP.

"He had to lock himself into the car."

The man was wearing green board shorts before he took them off, and black sunglasses.