Police are appealing for public help as they seek a man who exposed himself in front of two children at a bus stop in south-west Melbourne.

An unidentified individual engaged in a sexual act in front of children at the bus stop located at Dunnings Road and Point Cook Road in Point Cook, around 4:50 pm on Wednesday, July 2.

The children ran westbound on Dunnings Road away from the bus stop.

Investigators have released images of a man they believe could help with their enquiries.

He is perceived to be Caucasian in appearance, about 20 to 30 years of age, with a dark moustache and beard.

He was pictured wearing blue jeans, a black jacket and a black cap.

Anyone who witnessed the incident or has information that could help police in identifying the man is urged to contact Crime Stoppers.