McKellar has started what looms as a potential audition for the head coaching position with Larkham set to vacate the post at the end of the 2017 Super Rugby season.

Former Tuggeranong Vikings boss McKellar will take the reins while Larkham completes his Wallabies coaching duties on their grand slam bid in Europe.

His job will be blending new faces into to Brumbies squad with some players, including New Zealand playmaker Wharenui Hawera, trying to impress to win a full-time contract.

McKellar has already indicated he will apply to be Larkham's replacement, with the search for a new coach to start when the Brumbies appoint a chief executive.

The Brumbies board is finalising details of who the next chief executive will be, with a decision on the successful candidate expected to be made in the coming days.

McKellar said it would be business as usual in Larkham's absence and with the transition of up to 10 new players into the Brumbies set up.

"It feels different for me because I'm running the program for the next five weeks and we've been planning it for the last few months," McKellar said.

"It is different from that point of view because you're driving the meetings, standards and training sessions with the leadership group.

"But it also feels good, it's exciting and it's definitely something that I'm comfortable with."

Hooker Saia Faingaa is expected to join the squad for the first time on Monday after delaying his move to Canberra to be with his partner for the birth of their child.

Faingaa's twin Anthony and Nigel Ah Wong won't join Brumbies training until they finish their commitments in Japan while the club's Wallabies representatives won't be back until January.

Larkham will join the pre-season after the Wallabies spring tour of Europe.

Australian sevens player Tom Cusack impressed in a 1.2-kilometre time trial last week while flanker Chris Alcock and Tom Banks will join the team.

The Brumbies are trying to fill holes in the squad after the departure of some big names, including Stephen Moore, David Pocock and Matt Toomua.

Hawera is on a training contract and if he impresses, he will get an opportunity to fill the flyhalf role in the absence of Toomua and Christian Lealiifano, who is in Melbourne after a bone-marrow transplant as part of his treatment for leukaemia.

McKellar has formed an eight-man leadership group and said they were responsible for making sure the new-look squad fits together.

"There's an opportunity for guys to step up and you can just tell there's a real buzz around the group, like there is for most pre-seasons," McKellar said.

"The leaders have to make sure the new guys fit in, we've got a young guy like Rob Valetini from Melbourne who's moving out of home for the first time and last week was still in school.

"You can see the enthusiasm in the new guys, they're keen to throw themselves in and I think that fresh blood is a good thing. Sure we've lost some quality, but the guys we've brought in are good footballers."