John Norrish, 48, was reported missing at 8am on Saturday after he camped out with friends at Bakers Point in Narawntapu Friday night.

When he was reported missing, police urged members of the public in the national park through to Greens Beach and Beaconsfield to be on the lookout for Mr Norrish.

Emergency services had serious concerns for Mr Norrish's welfare due to an acquired brain injury, saying he was likely to become lost if disoriented.

An extensive search and rescue operation was launched and good news came on Sunday morning, when Mr Norrish was discovered by a helicopter searching to the east of the park entry.

Tammy Williams, Mr Norrish's sister, told The Advocate she had a hard night not know where her brother was.

"Sleepless isn't the word to describe last night," a relieved Ms Williams said, before thanking the rescuers and searchers.

"Thanks for everything, I can't wait to see him. Been thinking about him all night.

"When I arrived here this morning I started crying. Police rang last night to tell me he's missing. It's the second time and I couldn't believe it."

Mr Norrish was found in thick shrubbery, and was being treated by paramedics, Acting Sergeant Chris Martin from Tasmania Police said.

An update on the Tasmania Police Facebook page said Mr Norrish was "cold and tired but otherwise ok" and that "he had become lost in heavy bush land".

Constable Drew Oakden from the Westpac rescue helicopter crew said Mr Norrish appeared to be in relatively.

"He's being walked to a car at the moment and he doesn't have any major health concerns," he said.