Police allege the man has been involved in multiple instances of 'frottage', which constitutes a person rubbing up against another person in a crowd as a means of sexual gratification.
Swan Hill Police Inspector Haydn Downes says it's an unusual occurrence for the region.
"It happens a lot on crowded trains in metropolitan areas, but very rare outside of that," Downes said.
"If anyone has any concerns surrounding this, please give us a call and we'll take a statement and help."
The Swan Hill Police can be contacted on 5036 1600.