A press conference regarding Mr Smithies is being held in Wellington this afternoon.
More than 20 SAR volunteers, Wellington police maritime unit's launch - Lady Elizabeth IV - and the police national dive squad were involved in the search for Mr Smithies
His backpack was found about 1km south of Titahi Bay beach on Monday, providing search teams with a point of entry into the water.
Mr Smithies is a former publican in rural Southland who made a remarkable career change to become a university lecturer in economics.
Originally from Whanganui, he spent 18 years in the hospitality industry, including a stint at Pizza Hut, and about 13 years ago was working as a bar manager at a Tapanui pub, between Invercargill and Dunedin.
Mr Smithies told Radio New Zealand, as one of a series of 2008 interviews on career changes, that while Tapanui was a wonderful place for hunting and fishing, he got sick of drunks, fights, the hours, and he didn't want to just focus on getting people drunk.
"My greatest fear was I was going to get someone under the weather and they were going to drive and kill someone."
Despite having failed to pass his papers at a previous university stint, he returned in 1997 as an economics student.
Returning to university was "scary", he said, because he saw the young fellow students and thought "I have pubic hair older than most of these kids".
However, he focused on his work and getting out of the education system as much as he could.
He earned A pluses and found he loved mathematics. He stayed on at the university to lecture in economics.
Mr Smithies said he loved teaching economics and drew on his own history working in bars to teach the subject.
He left Otago University about two years ago to take up a position with the Commerce Commission in Wellington as a senior economist.
View Missing diver - how did he get to Hawkes Bay? in a larger map
- NZ Herald staff, NZPA