A man reported missing on Stewart Island since Monday has been located, after he survived on foraged shellfish and a deer he had shot.

The 39-year-old failed to return to his hunting group on Monday afternoon, but was found at 11.05am on Thursday.

The man was sighted from the air during an extended shoreline search at Chew Tobacco Bay.

Detective Alun Griffiths says he had become disorientated after knocking his head during a fall and his compass was later found to be reading incorrectly, because a knife was located close by.

Fortunately, he was able to sustain himself on the first night by eating a deer he had shot.

He was then able to forage for limpets, paua and other wild foods.

"This serves as a reminder to anyone entering the bush, even for a short time, to take a Personal Locator Beacon and a backup form of navigation.

"Police are grateful to Land Search and Rescue for providing teams in this challenging time."

-RNZ