In-form All Blacks halfback Piri Weepu is no certainty to start against the Wallabies in their Tri-Nations Test on Saturday after his arrival into Melbourne was delayed until Tuesday due to the birth of his first child.

New Zealand assistant coach Wayne Smith said coaching staff would wait until the No.9 joined the squad before making a decision on whether he or Jimmy Cowan would run on.

Weepu, who was a stand-out in the All Blacks' thumping win over South Africa earlier this month, and his wife had a baby girl on Sunday.

"It's a bit more difficult in that he hasn't been here for the start of the week so we'll assess that when he comes," Smith said after New Zealand training on Monday.

"He's been through an emotional time ... but we'll see how he is and then make some decisions."

While the All Blacks line-up remains unsettled, the Wallabies will be forced to make at least one change to the line-up which had a convincing 30-13 opening Tri-Nations win over South Africa in Brisbane on Saturday following the suspension of exciting five-eighth Quade Cooper.

Smith said he expected Berrick Barnes to come into the side, although predicted he would start at inside centre with Matt Giteau shifting to fly-half.

"I think that's how they'll play them and probably interchange them a wee bit, like what they did with Quade and Gits the other night, not too much will change," he said.

"Barnes is a very capable player, he's a player we've got a lot of time for.

"Whoever they play is going to be strong, going to be up for it, they're probably going to be on fire, whoever it is."

He didn't think the absence of dangerman Cooper would dent the Australian attack, which he described as difficult to defend against.

"As defence coach I've found them quite a difficult team to prepare for, a lot of different strategies, plays, and they switch the play quickly, they off-load well, they give a lot of inside balls.

"That's a team thing, not just a Quade Cooper thing."

Both sides had success against South Africa playing a ball-in-hand style and are expected to keep a similar strategy for the Etihad Stadium clash, which also doubles as the opening Bledisloe Cup match.

Smith said it would be a test of endurance for both sides.

"It's going to be a test for both 22-man squads, it's going to be test for the players' level of fitness.

"I think the winners are going to be the people who come along to watch it."

The match is expected to be a sell-out.

The All Blacks' final training at Etihad has been bumped due to Friday night's AFL clash between Essendon and St Kilda, however Smith wasn't concerned.

He said they still intended to inspect the ground surface, which has been repeatedly criticised as below-par.

"We will still make an appearance, we weren't going to have a run there anyway, just a walk-over."

Brought to you by AAP © 2024 AAP