It's understood Larkham will announce his decision on Friday morning and will move into a full-time Wallabies assistant coach job for 2018 and 2019 after guiding the Brumbies through the 2017 Super Rugby campaign.

It comes after Larkham was recognised as Australian rugby's coach of the year at the John Eales Medal on Thursday night while the Brumbies were the team of the year and community rugby duo Dougal Whitton and Deon Norval won volunteer awards.

Larkham has been juggling Brumbies coaching duties with a Wallabies assistant's role for the past two years and the double life has taken a toll on the World Cup-winning flyhalf.

He joins a list of some of Australian rugby's most respected figures who have either left or are leaving the Brumbies, despite the club making the finals in the past four seasons.

Wallabies coach Michael Cheika has been trying to recruit Larkham to a full-time role to boost Australia's chances of winning the World Cup in 2019.

Larkham did not want to leave the Brumbies stranded and signed a contract extension until the end of 2017, but he is set to then move into a Canberra-based Wallabies job.

The Brumbies have endured a turbulent year off the field and Larkham's looming absence will leave a massive hole at an organisation that has already lost chief executive Michael Jones, captain Stephen Moore, team manager Ben Gathercole and Wallabies Matt Toomua, David Pocock and Joe Tomane.

The silver lining to Larkham's decision is that the Brumbies will have 12 months to find a replacement once they appoint a new chief executive.

The Brumbies board is working through a list of chief executive candidates and is expected to finalise a decision before the end of the year on who will take the club's reins.

With Larkham on the verge of joining the Wallabies, one of the new boss' first jobs will be casting a wide net to search for a new head coach.

The Brumbies have battled their way through a year of off-field pain, despite making the Super Rugby finals for the fourth consecutive season.

Jones and the board of directors were engaged in an ugly legal battle before the parties eventually agreed to payout the chief executive's contract.

Moore has signed with the Queensland Reds, while Toomua, who ruptured his anterior cruciate ligament last weekend, is in England, Pocock is taking a sabbatical and Tomane has moved to France.

The Brumbies will also be without Christian Lealiifano, who will start his next chemotherapy treatment on the weekend before a bone-marrow transplant, while team manager Gathercole will move into a new role with Triathlon Australia.

The Brumbies believe they are in a solid financial position despite recent end-of-year losses and the board will deliver its plan for the future at an annual general meeting in December.

Larkham is one of Canberra rugby's favourite sons having guided the Brumbies to two Super Rugby titles and played a crucial role in Australia's World Cup triumph in 1999.

He moved into a Brumbies coaching position in 2011 after retiring and was elevated to a dual head coach position in 2014.

He has led the Brumbies into the finals in every year he has been a head coach, but is still chasing a drought-breaking championship.