(AFP) - World champions New Zealand claimed their biggest win over the Wallabies in Australia with a thumping 42-8 win over the defending champions to kick off their Rugby Championship campaign in Sydney on Saturday.

The dynamic All Blacks embarrassed the Wallabies six tries to one and have now lost only once to the Australians in their last 14 encounters.

It was New Zealand's biggest winning margin over the Wallabies in Australia since beating the home side 50-21 in Sydney in 2003.

It was Australia's fifth straight Test defeat after losing to the All Blacks 34-17 in last October's World Cup final along with three defeats at home to Six Nations champions England in June.

The Kiwis appear no closer to giving up the Bledisloe Cup they have held since 2003 with the two remaining trans-Tasman Tests against the Wallabies at home in Wellington and Auckland.

"I am very proud with the way the boys arrived for the kick-off and mentally we were right on the button," New Zealand coach Steve Hansen said.

"And when you're like that and you've got a bit of talent you can do things."

If Australia thought the chance of finally mastering the Kiwi powerhouse had arrived following the retirement of legends Richie McCaw and Daniel Carter they were sadly mistaken.

The Wallabies' hopes were shredded by a devastating opening half by the All Blacks, who smashed through porous defence for four tries to lead 32-3 at halftime.

It was a dynamic first half by the world champions, dominating territory and possession with the Australians seemingly incapable of mounting a resistance to the incessant waves of attack.

It got no better for the Wallabies with the Kiwis scoring a further 10 points in the second term.

"I thought we defended very poorly," Wallabies coach Michael Cheika said.

"Defence is attitude, so there's no rustiness. Let's get that one out of the way straight away. When players run you've got to tackle."

Exacerbating the Wallabies plight was a spate of injuries to their inside backs, Matt Giteau, Matt Toomua and Rob Horne, who all came off during the first half.

"They don't look too good, put it that way. But I haven't any details yet," Cheika said.

"It's not ideal (to lose three inside centres to injury) obviously. But you can always save yourself somehow."

Bernard Foley kicked an early penalty goal for the Wallabies but that was the only time the home side led and the All Blacks hit back quickly in the sixth minute.

Ryan Crotty broke through the tackles of Dane Haylett-Petty and Giteau to storm over for a converted try.

Giteau was forced from the field hobbling from an injured left ankle shortly afterwards to be replaced by Toomua.

Barrett kicked the All Blacks further in front with back-to-back penalties as the Wallabies struggled to get into the game against the fluent Kiwis.

The hapless Wallabies called on a second replacement when Toomua collided with Barrett and made way for Horne.

More disaster befell the Wallabies when Foley's clearing kick was charged down by flanker Jerome Kaino who scored for a 25-3 lead.

Nothing was going right for the Wallabies with a third back forced off with injury with Horne succumbing to a left arm injury.

The relentless All Blacks showed no mercy and scored their fourth try through left-winger Waisake Naholo after a scything run by Barrett.

The game looked well beyond the Wallabies' reach at half-time after an explosive opening half by the world champions.

Coach Cheika made a flurry of replacements early in the second half in a bid to spark his team as the All Blacks continued their points rampage.

Dane Coles scored after Tevita Kuridrani dropped a pass and then minutes later another replacement Julian Savea scored in the opposite corner for a 42-3 lead.

Replacement Nick Phipps scored the Wallabies only try with five minutes left.