Detective Sergeant John McCarthy said police had not been able to identify the man through formal police procedures such as fingerprints, photos and missing person records.
He had no identification or any other items on him when he was found.
"We are hoping that someone may know this person or at least recognise the tattoos," he said.
"Our next step is to look at forensic options such as dental records and DNA, but in the meantime we want to hear from anyone who might know who this man is.
"There will be a family out there missing someone so we would like to bring closure for them."
Anyone with information about the man were asked to contact Mr McGregor at Hawke's Bay Police on (06) 211 3810.