The man was in a St Peter Port bar when he allegedly punched a woman in the face and assaulted a member of staff, and then also headbutted a man in the street.
Officers would also like to speak to anyone who saw an altercation between two women on the dance floor.
The incidents happened between 01:00 and 02:00 on the morning of Sunday 29 October.
People with any information are being asked to contact Guernsey Police or to contact Crimestoppers anonymously on 0800 555 111.