McKenzie's audition for the All Blacks starting flyhalf role continues on Saturday against France. Photo:Kiyoshi Ota/EPA

WELLINGTON – Damian McKenzie's audition for the All Black starting flyhalf role continues on Saturday in the third and final Test against France, but it is just one of several 2019 World Cup subplots set to unfold in Dunedin.

McKenzie has been given the first opportunity in his 14-Test career to start in the pivotal role after Beauden Barrett was ruled out with a concussion sustained in the All Blacks' 26-13 second-Test win in Wellington that sealed the series.

Coach Steve Hansen has also opted to give some of his fringe and uncapped players a chance to prove they can step up to international level.

Hansen named four debutants - centre Jack Goodhue, loose forward Shannon Frizell, flyhalf Richie Mo'unga and lock Jackson Hemopo - in his 23-man squad for the game at Otago Regional Stadium on Saturday (kickoff 9.35am SA time).

Just two of the forwards - captain Sam Whitelock and prop Owen Franks - have played more than 50 Tests, while five of the eight replacements can total just seven caps between them.

The decision to slot in McKenzie as a replacement for two-times World Rugby Player of the Year Barrett, however, has attracted the most attention because many observers felt Mo'unga was the better fit to start.

McKenzie's two performances at flyhalf at international level - he started for the Maori All Blacks against the British and Irish Lions last year and played almost 70 minutes last week - have not been as impressive as his times at fullback.

Steve Hansen has opted to give some of his fringe and uncapped players a chance to prove they can step up. Photo: Chris Ricco/BackpagePix

Hansen, however, said he had faith in the 23-year-old Chiefs pivot, though it would take some time for him to grow into the role.

"Damian is coming along nicely," Hansen told All Blacks TV. "He's shown us that he can play genuine Test rugby as a fullback.

"He came on the other night (and) had a good stint at first-five for us, and he did okay. Whilst he didn't set the world on fire, the whole team didn't.

"He's got some special skills, and he's been working hard on his game. I'm confident we'll see a pretty good performance from him."

While the series has already been lost by the French, coach Jacques Brunel sprang something of a surprise with his decision to drop skipper Mathieu Bastareuad, with scrumhalf Morgan Parra getting the captaincy.

Wesley Fofana will make his first Test appearance in 18 months alongside Clermont teammate Remi Lamerat in a speedy and skilled midfield combination, which could be a real handful for the All Black inside backs.

France's loose forwards Kevin Gourdon, Kelian Galletier and Mathieu Babillot were impressive last week in Wellington where they dominated the breakdown and gave their team momentum.

The French tight five, particularly their front row, have also impressed with their scrummaging, ball-handling skills and speed around the field and are looming as a real threat at next year's World Cup.