The hawksbill was less common than the green turtle, the species found on 90 Mile Beach last month, and usually preferred tropical reefs, where it fed on soft coral and invertebrates.
Mr Godoy said the barnacles on this specimen's shell suggested it had been unwell and floating at the surface for a few weeks, at least.
Adults grew to 80kg, taking their name from their distinctive beak-like bill.
They were critically endangered, having been hunted to the brink of extinction for their shells, which were used for tortoiseshell ornaments.
The past year had set a record for the number of turtles rescued in Northland, and for the number that had survived, Mr Godoy added.
Currently Kelly Tarlton's was looking after eight turtles - two hawksbills (with the new arrival to come), four green and one olive ridley. Turtles found on the shore should not be returned to the water, Mr Godoy said.
They were trying to beach themselves for a reason, usually because they were ill.
Anyone who found one should call the 24-hour DOC hotline 0800 DOC HOT.