Preston police say Matthew Parkinson, wanted in connection with a sexual assault, presents a "risk to the public".
Parkinson, 26, was convicted of battery, theft and assault in November 2018.
When he was let out on license in May, he breached the terms after breaking a curfew and has been wanted since.
Police now say that he is also wanted in connection with an investigation into alleged sexual assault in Bamber Bridge in June.
Parkinson, who has links to Preston, Bamber Bridge, and Cumbria, is white, 5'11, of medium build, with blue eyes.
Detectives are urging people not to approach him but instead contact police immediately if you know where he is.
Det Con Catherine Thomas, of Lancashire Police, said: “Parkinson presents a risk to the public and could be violent if approached.
“We would urge anyone who knows where he is to come forward and contact police.
“Furthermore I would ask Parkinson, if he sees this appeal, to speak to us immediately.”
Anyone with information can contact police on 101 or (01257) 246132 or email email@example.com or