Thomson will end a 24-year rugby administration career on December 31 when he steps away from the game and opts against returning to his role as the ARU integrity manager.

Thomson was appointed interim Brumbies chief executive seven months ago following an ugly boardroom war between the club's directors and former boss Michael Jones.

The former ACT rugby representative and inaugural Brumbies team manager in 1996 became the voice of reason in Canberra's rugby community and helped mend broken bridges in the capital.

The Brumbies board was keen to find a role to keep Thomson involved at the club, potentially as a general manager of high performance, but Thomson decided it was time to try something new.

"It's been an enjoyable seven months even though I came in at a difficult time, I enjoyed coming in and engaging with a wide-range of people," Thomson said.

"We worked through a lot of the issues we had and hopefully the things we've put in place since then can assist the organisation moving forward into 2017 and beyond.

"There were a lot of challenges, but nothing insurmountable. It was just about engaging with people and improving on what's been done in the past."

Thomson will finish his stint at the Brumbies on Friday and is set to remain in Canberra after commuting to Sydney in recent years to work at the ARU.

He has been working to finalise player contracts, including Wallabies lock Rory Arnold's new deal, while playmaker Wharenui Hawera is set to be signed and the Brumbies are locked in negotiations with Tevita Kuridrani.

Brumbies chairman Robert Kennedy praised Thomson, a former AFP detective, for giving the Super Rugby club stability when it needed it most.

"Phil's level and depth of knowledge of the rugby industry has been invaluable to the board setting us up and taking us forward from here," Kennedy said.

"He's helped set us up for the selection of a new coach and general manager of high performance, he brought a huge amount of knowledge with him.

"Phil was doing far more than warming a seat. He was adding a huge amount and we're very appreciative of all he's done. We would have found any role for him, but they probably would have been below him in terms of skills and knowledge."

Michael Thomson will step into the chief executive role in January after leaving his job at the Australian Sports Commission.

The Brumbies have also advertised for a new coach, with Stephen Larkham set to leave at the end of 2017 to start his full-time Wallabies assistant coaching job.

It is hoped the Brumbies will be able to appoint Larkham's successor by the end of February to allow for a handover period and for the new coach to play a role in player recruitment and retention.

The Brumbies have a massive list of off-contract players and will be fighting overseas clubs and Super Rugby rivals to keep their roster together.

Thomson will tie up loose ends this week as he prepares to end a career that has gone full circle.

He was the ACT under-21s team manager from 1993-95 before joining the Brumbies for their first season in Super Rugby, working with the likes of Larkham, George Gregan and Brett Robinson for five seasons.

Thomson then became the Wallabies team manager for nine years before taking a role as the ARU integrity manager.

"For Phil to finish as chief executive of the Brumbies is a good top and tail for his rugby career," Kennedy said.