All Blacks legend backs Dave Rennie to revive Wallabies following World Cup disaster

All Blacks great Andrew Mehrtens believes New Zealand's loss will be Australian rugby's gain, declaring Dave Rennie will reinvigorate the Wallabies after more than a decade in the doldrums.

Mehrtens expects Rennie to leave no stone unturned in his quest to revive the Wallabies, even tipping the meticulous mentor to reach out to Michael Cheika for possible pointers.

Rennie, who guided the Chiefs to back-to-back Super Rugby titles in 2012-13, rejected overtures from New Zealand powerbrokers to take over from Cheika after completing his commitments with Glasgow Warriors next June.

The Season: Hamilton Boys High School - Episode 3

"That shows the integrity of the guy. He's a Kiwi and it must be flattering to be asked to put your name in the ring for that All Blacks job," Mehrtens told AAP.

"But he's made his decision and already it seems like he's pouring everything into it, to have that attitude when New Zealand came knocking.

"I'm sure they're not delighted at the fact that a) they're not getting to use his IP now and b) a close rival is."

Hailing Rennie as understated - "like we like it in New Zealand" - with street smarts, Mehrtens believes the new coach's pragmatic approach will be the perfect fit for the Wallabies.

"Coaching is so much about man management and helping the players develop and far less these days than the actual technical coaching side," he said.

"For the last 15 years or so the focus of Australia's last few coaches has been very much off the mark," he said.

"A lot of the focus, whether it be skills coaching or club coaching, has been around whiteboards - dividing the field up, a very methodical approach and a very strict approach.

"That takes away from the players' ability to make decisions on the field and to behold the game themselves, which they need to be able to do.

"And that will take some time to turn that around and change that."

"I have very little doubt they will be trying to catch up at some point. I'm sure 'Cheik' will want the best for Australian rugby and the Wallabies enough to give 'Renns' the benefit of his experience of the last four years," Mehrtens said.

"And I'm sure Renns is a big enough guy to say 'look, I'm new coming in to this environment, I might know a lot of the players; I've watched them over time with Super Rugby or whatever but I want to learn as much as I can about the internal workings as well'.

"It will probably be in a dark room somewhere over a beer but it wouldn't surprise me at all if we saw that sooner rather than later.

"I wouldn't be surprised if Cheik went over to Scotland and caught up with him."

AAP

In other news: