The Wallabies haven't held the Bledisloe Cup since 2002 and but Deans believes they have a great opportunity to upset the world champion All Blacks and start the three-match series with a win in Sydney on Saturday night.

New Zealander Deans coached Australia from 2008-13, tasting victory just three times in 18 Tests against the All Blacks.

The veteran coach said Michael Cheika's Wallabies must be mentally fierce and have a strong belief they can win.

"That's the great hurdle, that mental hurdle," Deans said.

"You've got to believe first before it happens. If you don't believe it, it just simply won't happen.

"I've got no doubt they're doing a lot of work on that side of the game, and they're developing depth.

"The Wallabies have got a vibrant young group. They've got some bigger frames up front and in the backline, and they showed in the recent outing it can be done. I'm expecting a great encounter."

In last year's series opener, the Wallabies trailed 54-6 in Sydney before losing 54-34.

Although the Wallabies beat NZ 23-18 in the series finale in Brisbane, the All Blacks had already secured the trophy by then after escaping with a narrow home win in the second match.

Star Wallabies flanker David Pocock missed that series because of his year-long sabbatical, and the All Blacks are on red alert for his presence this time around.

Deans, who coached Pocock at the Panasonic Wild Knights in 2016, believes the 30-year-old will make a big impact.

"He's a bloke that can stop the game," Deans said.

"He's unique with his ability and skill set. More importantly he's grown as a leader, and his influence on the players around him is obvious and significant."

Deans believed it was a good time for Australia to catch the All Blacks.

"This weekend is a great opportunity for Australia, no doubt about it," he said.

"The Wallabies have been lying in wait preparing.

"A nucleus of the All Blacks have had the distraction of having to resolve the Super Rugby comp, and then they've just come together for a week's prep.

"It's an opportunity the Wallabies won't want to miss."

Deans is in Perth with his Wild Knights side preparing for Friday night's World Series Rugby clash with the Western Force at nib Stadium.

Australian Associated Press