Police are appealing for information about an unidentified assault victim in the Hawke's Bay town of Haumoana.

The man was found unconscious about 7am on Monday and taken to Hawke's Bay Hospital, where he is in a critical condition.

Detective Inspector Mike Foster said police want to speak to anyone who might have seen the man in the area of Grange Road North and Domain Road.

He is believed to be in his mid-40s, has long scraggly brown hair and was wearing a long-sleeved red top and dark blue shorts.