The childhood friends will anchor Australia's scrum at ANZ Stadium on Saturday night and are bracing for a New Zealand onslaught as the Wallabies aim to end their trans-Tasman woes.

It will be another massive moment for the ACT Brumbies duo, who grew up in western Sydney dreaming of wearing Wallabies gold.

But 26 years after their dads played together for Samoa at the 1991 World Cup, Alaalatoa and Sio are ready to start building their own international legacy.

They took the first steps in their Wallabies partnership when they were the starting props against Italy in June, but a clash against the powerful All Blacks will be the litmus test.

"It is special being able to do it with Scotty, it definitely does make me more comfortable knowing that he's there on the other side with me," Alaalatoa said.

"I see it as a huge blessing. We grew up together not too far [from ANZ Stadium] and to be able to represent our country and families together, it's a huge honour.

"We've got a strong connection on the field and hopefully that's beneficial for us. We're always honest with each other on the field because we know each other so well.

"Being able to run out in a Bledisloe Cup game together and starting is something I probably thought would never happen. I always watched Scotty, he's a few years older than me.

"But it's slowly happened and we've got this opportunity so that's huge. We need to make the most of it."

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The Bledisloe Cup atmosphere is still foreign to Alaalatoa, who had never attended a Wallabies-All Blacks clash in Sydney until he made his international debut 12 months ago.

Dads David Sio and Vili Alaalatoa will sit together as part of a massive family army as the Wallabies launch their bid to end a five Test losing streak against New Zealand.

Sio has established himself as the No. 1 loosehead prop in Australian rugby and doubles as the perfect sounding board for Alaalatoa, who has enjoyed a boom year on the other side of the scrum.

Sio, 25, has played the big brother role for Alaalatoa for most of their lives, helping ushering him into the Brumbies ranks and then the Wallabies.

His presence has helped fast-track their Super Rugby combination and Alaalatoa is adamant it will help them prepare for the Bledisloe cauldron.

"Yeah, we're always together. Some of the [Wallabies] boys give us plenty of stick, they reckon we're twins," Alaalatoa said.

"I was the same age as Scotty's brother, Pat, and he's the same age as my brother [Michael]. So Pat and I were always the little smartarses ... Mike and Scotty would always whack us down."

The Wallabies haven't won the Bledisloe Cup since 2002 and have won just five of the past 37 Tests against New Zealand.

The trans-Tasman struggles were highlighted in Super Rugby this year when New Zealand teams won all 26 derbies against Australian sides.

But Sio and Alaalatoa have inside knowledge given Mike Alaalatoa was part of the Canterbury Crusaders' championship-winning team and Pat Sio is playing in the Kiwi domestic competition.

Scott Sio is confident the Wallabies can end the All Blacks hoodoo, backing coach Michael Cheika's preparation to have them ready to topple the world champions.

"You have to be confident. There's no point if we don't believe it and we feel we can get the job done," Sio said.

"Any game you play for Australia and that's the way you treat it. Allan and I are so close so we know we're comfortable with the challenge.

"This weekend we're playing against one of the best teams in the world and one of the best front rows as well. This is a chance to prove us ourselves and see how we're tracking as a combination."