But ACT Brumbies coach Larkham says the battle lines have not been blurred and his future role as part of Cheika's Wallabies team is the furthest thing from his mind on the eve of a blockbuster Australian derby.

The players are adamant Wallabies selection is the furthest thing from their minds, but they have a chance for the perfect audition in front of the Test coaching staff.

Cheika and Larkham spoke just days before the Brumbies take on the NSW Waratahs in Sydney to organise a Wallabies planning meeting for players next week.

It's an unusual situation for coaching combatants so close to a crucial match, but both Larkham and Cheika are juggling their respective Super Rugby title ambitions and Australia's hopes of lifting the World Cup.

Cheika is trying to instil a mantra of "bash each other" in Super Rugby and then team up for Wallabies success.

So for a brief moment this week, interstate and cross-border shots were put on hold to join forces and talk Wallabies tactics.

"We're talking to each other and but were weren't saying what we're going to do this week ... it's not about the coach dominating the other coach. It's about the players getting out there," Larkham said.

"[Super Rugby roles] don't affect what we're trying to achieve at the [international] level. We had a really brief conversation this week, but we certainly didn't talk about the game.

"It was about a little get together [for the Wallabies] next week. It doesn't affect your preparation, I'm focused on what we're trying to achieve as a team and my focus is the Brumbies, not the other stuff."

Cheika has added Larkham to his Wallabies coaching team for the World Cup to mastermind Australia's attack at the tournament later this year.

Larkham agreed to the role, but made it clear his No. 1 priority was the Brumbies and that he wouldn't let Wallabies plans affect his mission to end the ACT's title drought.

The Cheika-Larkham coaching battle adds another layer to the Waratahs-Brumbies rivalry, which started when NSW rejects moved to Canberra for a chance to play Super Rugby in 1996.

Australian conference bragging rights are up for grabs this weekend and the Brumbies are intent on proving their title credentials against the defending champions.

The Waratahs knocked the Brumbies out of championship contention last year when they romped to a 29-8 semi-final win.

The Brumbies have failed to score more than eight points in each of their last three matches in Sydney.

"But we're looking forward. This is the No. 1 game so far this year ... we're not looking too far ahead. It's a grand final every week for us, and it's not different this week," Larkham said.

Larkham has resisted the temptation to throw returning flanker David Pocock straight back into the starting side in his comeback from ankle ligament damage.

Former Wallabies skipper Pocock has played just six games since the start of the 2013 season after two knee reconstructions.

But Larkham said his replacement, Jarrad Butler, deserved to retain the No. 7 jersey while Ita Vaea has been a powerhouse at the back of the scrum.

"We definitely want to reward [Butler and Vaea] but equally we want to get Poey back in there," Larkham said.

"Poey had a long layoff with his knee, but started exceptionally well when he came back. But JB and Ita are playing extremely well at the moment."

Butler can lay claim to being the hardest working forward in the Australian conference, putting his body on the line to make 62 tackles per game this season.

Waratahs flanker and incumbent Wallabies skipper Michael Hooper is the next best Australian with 56 tackles.

"JB definitely has the highest amount of ruck involvements of anyone in our team, so he's definitely getting around," Larkham said.

"He has been working on being a bit more dominant over the ball, but his work rate around the ground is unsurpassed.

"And in Poey we've got a world-class player coming off the bench bringing that skill to the game."

Sunday: NSW Waratahs v ACT Brumbies at Allianz Stadium, 4.05pm. TV time: Live on Fox Sports 2.

Brumbies team: 15. Robbie Coleman, 14. Henry Speight, 13. Tevita Kuridrani, 12. Christian Lealiifano, 11. Joseph Tomane, 10. Matt Toomua, 9. Nic White, 8. Ita Vaea, 7. Jarrad Butler, 6. Scott Fardy, 5. Sam Carter, 4. Rory Arnold, 3. Ben Alexander, 2. Stephen Moore, 1. Scott Sio. Reserves: 16. Josh Mann-Rea, 17. Ruan Smith, 18. Jean-Pierre Smith, 19. David Pocock, 20. Jordan Smiler, 21. Michael Dowsett, 22. James Dargaville, 23. Lausii Taliauli.

Waratahs team: 15. Israel Folau, 14. Taqele Naiyaravoro 13. Matt Carraro, 12. Kurtley Beale, 11. Rob Horne, 10. Bernard Foley, 9. Nick Phipps, 8. Wycliff Palu, 7. Michael Hooper, 6. Jacques Potgieter, 5. Dave Dennis, 4. Will Skelton, 3. Sekope Kepu, 2. Tolu Latu, 1. Benn Robinson. Reserves: 16. Hugh Roach, 17. Jeremy Tilse, 18. Paddy Ryan, 19. Sam Lousi, 20. Mitchell Chapman, 21. Stephen Hoiles, 22. Brendan McKibbin, 23. Jono Lance, 24. Peter Betham.