Police are trying to track down a man who they say was masturbating in his SUV in front of a woman in west Hamilton on Wednesday.

Around 3 p.m., a 20-year-old woman was walking along Leland Street heading towards Ward Avenue, not far from McMaster University.

As she was walking, a dark gold Jeep Grand Cherokee pulled up next to her, police say.

"Which is when she noticed that the man driving had his jeans unzipped and was exposing himself and believed to be masturbating," a police news release reads.

The woman said she was calling the cops, and the driver sped off, going south.

The man is described as white, in his 50s, with a medium build, an unshaven face and a greying moustache.

He was wearing a black T-shirt and blue jeans.

Police say his vehicle had "several rust spots throughout."