Smith replaces Tony Ensor at fullback and Ellison will play at centre, instead of Jayden Spence.
They have been released by the All Black management to play in the game before the squad heads overseas to Argentina and South Africa.
"Getting guys with that experience back in the side is good for everyone," Otago coach Tony Brown told the Otago Daily Times.
Otago has a young and inexperienced team that will relish the boost given by the the two All Blacks.
"It will give the young boys the confidence to go out there and play," Brown said.
"Ben and Tamati give us the experience and hopefully, it flows through the team."
The All Blacks had a light jog with the team on Sunday and joined the full practice at the Forsyth Barr Stadium yesterday.
The other changes in the team have been caused by injuries.
Liam Coltman will play at tighthead prop because loosehead prop Scott Manson is out of action for two weeks with an ankle injury. Tama Tuirirangi has been switched from tighthead to loosehead.
Gareth Evans replaces TJ Ioane at blindside flanker because Ioane has hamstring niggles.
Brown was disappointed with the second-half performance when Otago was beaten 43-12 by Counties-Manukau on Friday night.
"At halftime we were playing well and were right in the game, Brown said. "I thought we had the ascendancy on them.
"We made a couple of crucial errors at the start of the second half that gifted them points and, with our inexperience, it was hard to come back from that."
It was a hard lesson for the young team and Brown made sure that his team remembered the lessons from that game.
"We have to eliminate the errors and each player must focus on their own job," Brown said.
"We gave Counties points and tries. If we can cut those errors down we will be fine."
The experienced Tuirirangi, a key player in the Otago scrum this year, has also worked hard around the paddock with his tough hits in the close-quarter exchanges and his covering work.
Japanese international Fumiaki Tanaka has been the most impressive halfback on show in the ITM Cup with his quick and accurate passing and high work-rate.
James Semple, who was a late scratching before the Manawatu game, returns to first five-eighth for North Harbour.
North Harbour let a winning chance slip when it was beaten 23-20 by Manawatu in the last round. Defensive errors in the red zone and shaky set pieces allowed Manawatu to take the win.
A key player in the North Harbour team is towering lock Chris Smith, who is expected to be dominant in the lineout.
Otago has played North Harbour 32 times and has won 21 of the games, to North Harbour's 11. Otago won 46-29 last year.
Otago v North Harbour
Forsyth Barr Stadium, tonight, 7.35pm.
Referee: Shane McDermott.
Head to head: Played 32; Otago 21, North Harbour 11.
TAB odds: Otago $1.30, North Harbour $3.30.
Otago: Ben Smith, Marshall Suckling, Tamati Ellison, Glenn Dickson, Buxton Popoalii, Hayden Parker, Fumiaki Tanaka, Paul Grant (captain), Lee Allan, Gareth Evans, Rob Verbakel, Tom Franklin, Liam Coltman, Sam Anderson-Heather, Tama Tuirirangi. Reserves: Shota Horie, Aki Seiuli, Adam Hill, TJ Ioane, Brad Weber, Peter Breen, Tony Ensor.
North Harbour: Rudi Wulf, David Raikuna, Cory Aporo, Francis Saili, Nafi Tuitavake, James Semple, Bryn Hall, Vili Fihaki, Malakai Ravulo, Irwin Finau, Apisalome Ratuniyarawa, Chris Smith, Ben Afeaki, James Parsons, Salesi Manu.
Reserves: Manu Leiataua,Alex Woonton, Glenn Preston, Sam Hayes Stevenson, Brenton Helleur, Pita Ahki, Luke Devcich.
