A man is wanted by police after dropping his shorts and masturbating in front of two teenage girls at a Melbourne beach.

The two girls were sitting on the foreshore at Beaumaris beach on Friday, January 8, when a man approached them.

A computer-generated image of the man police wish to speak to over a masturbating incident on Beaumaris beach. Credit:Victoria Police

He asked if he could take a photo of them.

When they declined, he walked to a spot on the beach about 10 metres away, dropped his shorts to his knees and began to masturbate.

The two girls ran from the beach and told their parents, who called police.

Police have released a computer-generated image of the man and have asked anyone with information to call Crime Stoppers on 1800 333 000.