Coach Ewen McKenzie says the Wallabies are facing one of their ''greatest challenges'' against Scotland on Saturday after losing eight of their match-day squad in a horror week of controversy and injury woes.

Less than 48 hours after notching their first back-to-back wins in a year, six players - all of whom played against Ireland last Saturday - were suspended for drinking too much on a night out in Dublin in the lead-up to the match.

Tevita Kuridrani fell next, banned for five weeks for a tip tackle, and Matt Toomua followed with a tour-ending hamstring injury.

McKenzie was forced to make four changes to his back line and a further four to his reserves, plus call for outside-back reinforcement in NSW winger Peter Betham. He named the team three days later than usual due to the upheaval.

McKenzie said it would be one of the biggest hurdles the team has faced so far, but it would not be an excuse for anything less than a win against the Scots at Murrayfield.

''The circumstance is what it is this week, we're not going to use it as an excuse around playing Scotland,'' he said.

''It will be one of our greatest challenges, given we have a bunch of changes. The guys are going to be hungry for different reasons, so if you don't get the best out of them now I don't know when you will.

''This is a test of character for everyone, for all of us, the coaches, the whole lot. It will be an important moment.''

Versatile Queensland back Mike Harris has been parachuted into the line-up at No.12, with Christian Lealiifano starting outside him and taking over the kicking duties from five-eighth Quade Cooper.

Joe Tomane and Reds rookie Chris Feauai-Sautia will shoulder the burden of being finishers after taking over from Nick Cummins and Adam Ashley-Cooper on the wings. Bernard Foley will cover a number of positions off the bench, while Nick Phipps also comes into the squad alongside Nic White.

Liam Gill, suspended alongside five others, makes way for Ben McCalman in the reserves; Saia Fainga'a replaces Tatafu Polota-Nau, also suspended, and Ben Alexander fills in for Benn Robinson, another of the outed players.

''It wasn't a calculated decision, I didn't say, 'I've got these players up my sleeve','' McKenzie said of the terrible timing of this week's events.

''You just make a decision and then get on with it. Injuries are a part of it, so you just deal with it.''

McKenzie said he had planned before the tour to look to eligible Europe-based Australians to plug gaps if they arose.

The incident in Dublin last week changed his mind. ''In the end, with the issues earlier in the week, I made the resolution that this group would solve [the problem],'' he said. ''We're in a bit of a hole but we'll solve it as a group.''

McKenzie said he spoke to the players about moving on and preparing to face Scotland.

''Nothing's going to change so we have to suck it up and get going,'' he said. ''What we can change is how we function as a group, so we'll pull together. You circle the wagons and get on with it.''

Australia: Folau, Tomane, Lealiifano, Harris, Feauai-Sautia, Cooper, Genia, Mowen (c), Hooper, Fardy, Horwill, Simmons, Kepu, Moore, Slipper. Replacements: Fainga'a, Alexander, Ryan, Timani, McCalman, White, Phipps, Foley.