The Wallabies will get a litmus test of their forward strength against England in their opening Test in Perth on Saturday night.
But it won't be the end game on McKellar's watch as he looks to make the Wallabies' maul - a major weapon for the Brumbies in Super Rugby - a world beater.
"We're trying to develop a mindset here of having the best maul in the world," McKellar said on Wednesday.
"That takes time, there's five groups of players that come from different franchises and they all do it differently."
"The reality is in Test match games are often tight ...opportunities are less, but when we do take them we've got to be better.
"Mauling's one part of it, there's a whole lot to being a good forward pack, but it's an area that we've identified that can certainly make some shifts."
Despite a dry track predicted at Optus Stadium, the forward battle is expected to be key in deciding the three-Test series with England priding themselves on their work up front.
McKellar said they knew what was coming.
"It's been part of English rugby DNA for forever and a day that set-piece and physicality and brutality is important and it's certainly going to be important for our pack," he said.
"We know that for us to win this game we've got to win the collisions and we've got to look to dominate at set-piece - it's as simple as that.
"They're world class and it's a real challenge for us and if we do that you allow the backline to really shine and dominate.
"They'll be strong at set-piece; (Maro) Itoje and (Courtney) Lawes, Jamie George; they're world class so it's an enormous challenge for us."
With the team to be named Thursday the Australians could be without world-class prop Taniela Tupou, who has been battling a calf injury, with McKellar cagey on whether the Reds bruiser will play.
"There's no doubt he would be a loss ... he's a point of difference player and has got a pretty unique skill set Taniela," McKellar said.
"He's incredibly powerful at scrum time and he also brings a point of difference in open play.
"There's other areas of his game where he's starting to value and wanting to improve but we're fortunate that if he's not available, guys like Alan Alaalatoa and others can step up and certainly do a job for us."
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