New Zealand second row Brodie Retallick will make his comeback from injury in Sunday's World Cup game with Namibia.

Retallick, regarded as one of the world's best locks, has been out since dislocating his shoulder in July and returns earlier than expected.

The two-time defending champions make 12 changes, including resting both Richie Mo'unga and Beauden Barrett.

That means Barrett's brother Jordie, a utility back, will play fly-half for the first time in international rugby.

"He has played there before at a lower level," coach Steve Hansen said.

"He has got the skill-sets we believe to be able to run the game and the confidence and the skill-set to be able to execute as well as run it.

"We're reasonably confident he will be fine."

After picking up his injury against South Africa earlier this year, there were fears Retallick - the 2014 world player of the year - would be ruled out of the World Cup in Japan.

However, he was named in the All Blacks' squad with the hope of featuring in the knockout stages and returns for their penultimate pool game.

New Zealand are currently second in Pool B with two wins from two games, including a 63-0 thrashing of Canada on Wednesday.

"It's exciting to have the big fella back," Hansen said.

"You go back to the night it happened and there was a bit of despair. Then we found out it wasn't one of those dislocations that would require an operation and there was more hope.

"As he has trained he has got better and the guys have got more excited, none more so than the coach."

Captain and centre Johan Deysel makes his first start of the tournament following injury for Namibia in one of nine changes from their 57-3 defeat by South Africa.

Deysel scored a try when these sides met at the 2015 World Cup, a game the All Blacks won 58-14.

Teams

New Zealand: Smith, Reece, Goodhue, Lienert-Brown, Bridge; J Barrett, Smith; Moody, Taylor, Laulala, Retallick, Whitelock, Frizell, Cane, Savea.

Replacements: Coles, Tuungafasi, Ta'avao, Tuipulotu, Todd, Weber, Perenara, Ioane.

Namibia: Tromp, Klim, Newman, Deysel, Greyling; Kisting, Stevens; Rademeyer, Van Jaarsveld, De Klerk, Van Lill, Uanivi, Gaoseb, Forbes, Venter.

Replacements: Nortje, Theron, Coetzee, Retief, Booysen, Jantjies, De La Harpe, Du Toit