Steve Hansen backs Richie Mo'unga and Beauden Barrett to shine for All Blacks as unit in Rugby Championship

Trying pair as a combination in Saturday's clash with South Africa

Richie Mo'unga, right, and Beauden Barrett, left, have been backed to excel in their new roles for New Zealand. Getty

Steve Hansen has been pondering playing Richie Mo'unga and Beauden Barrett together for 'quite a while', the All Blacks coach said on Thursday, and Saturday's Test against the South Africa was just the right time to give it a go.

Hansen sprung a surprise when he named his team for the Rugby Championship clash in Wellington by moving the two-times World Player of the Year Barrett to full-back and giving Mo'unga the fly-half jersey in only his third Test start.

While Mo'unga's Test career began only last year off the bench against France in Dunedin, his form for the all-conquering Canterbury Crusaders has proved impossible to ignore.

"It's probably time," Hansen said on Thursday. "We've got a plan with a whole lot of things that we want to do before we get to the nitty gritty business (of the Rugby World Cup) and we just felt Saturday's the right time to try that particular part of the plan."

While something of a surprise given the intensity of All Blacks-Springboks Tests, the move is a continuation of a tactic employed last year when Hansen fielded twin playmakers with Damian McKenzie at fullback and Barrett in the No 10 jersey.

Hansen was robbed of that option when McKenzie was lost for the year to an ACL injury but Mo'unga's strong form has enabled a reworking of it, albeit with the quicker Barrett moving back into the No 15 shirt after 36 straight Tests at flyhalf.

"I've often said if the reward's worth the risk, then take the risk," Hansen said. "Obviously to replace Beauden at first five you've got to have someone that's pretty good.

"Richie's been playing very well for the last couple of years and at some point you want all your good players on the park, and both of them are world class."

While experimentation this close to a World Cup, as New Zealand bid to win the competition for a third time in a row, tends to cause consternation among fans, Mo'unga has looked assured in his nine previous appearances.

He is also used to filling big shoes, having slotted seamlessly into the starting fly-half role at the Crusaders in 2016 after the departure of Dan Carter.

Mo'unga quickly drew comparisons with international rugby's all time leading points scorer and his All Blacks teammates suggested on Thursday that those comparisons were not too wide of the mark.

"Off the field he can be a bit of a clown," hooker Codie Taylor said. "What he brings to the table is an unreal skillset and the ability to back himself in little moments and give it a crack."

Flanker Matt Todd, who played five seasons with Carter at the Crusaders, also felt that Mo'unga was unflappable.

"He's calm under pressure. He doesn't get flustered by any situation," Todd said.

"He's got an old head on young shoulders (and) he creates things out of nothing."