The heat is on the Brumbies after two disastrous weeks, which have seen their Australian conference lead narrowed to just two points with rivals the NSW Waratahs lurking in the shadows.

The Brumbies have won just one game in the past five weeks, are battling injuries and face a testing month before they get a full-strength team back on the field.

Their losses include a sloppy 13-8 defeat at the hands of the Melbourne Rebels on Saturday night and a loss to the Auckland Blues - two teams ranked 11th and 14th respectively.

Their run against the Otago Highlanders on Friday night, a derby against the Waratahs and a two-game tour of South Africa will decide whether the Brumbies are title contenders or pretenders.

"I think every week there is a lot of pressure ... the last two weeks we've been very disappointed with one or two decisions which have swung the game," Larkham said.

"We're not going to lose our head on that performance, but we know every week is a tough game. We've got to try to get a little bit of momentum over these next four games.

"We're not going to change anything, we're not worried about where our game is and there's no systemic problem with our game. It's merely a case of circumstances getting the better of us."

The Brumbies are hopeful they'll have more players on deck this week after struggling with a growing injury toll.

Jesse Mogg and Tevita Kuridrani could come into selection contention while Nic White is rated only a slim chance of being fit to play the Highlanders in an Anzac match.

Larkham will seek clarification from referees' boss Lyndon Bray this week about the way the rolling maul is policed.

The Brumbies were privately fuming that referee Angus Gardner did not penalise Scott Higginbotham for tackling David Pocock from what they perceived as an illegal position at the back of a maul.

Higginbotham made the tackle with Pocock about to dive over the line, deliberately stopping a Brumbies try that could have lifted them to victory at Canberra Stadium.

The Brumbies use the maul as one of their biggest weapons, but teams have found a way to disrupt the set move and force the Brumbies out of their comfort zone.

Larkham felt Rebels skipper Higginbotham should have been penalised and expressed frustration at inconsistencies in the way the maul is officiated.

"For the majority of the game I thought the refereeing was superb ... we didn't get any penalties in the first 30 minutes but I thought we didn't deserve any and we deserved the ones that went against us," Larkham said.

"But it's a huge moment in the game when our strength is nullified because the referee can't get the right decision there."

The Brumbies' scrum was overpowered in the first half as Jean-Pierre Smith stepped in to replace Wallabies loosehead prop Scott Sio.

"[The scrum] was a disappointing part of our game, particularly in the first half," said Brumbies captain Stephen Moore.

"The Rebels' scrum was really strong and we didn't adapt to it. That's a work-on for us this week."

The Brumbies are hopeful of Lausii Taliauli being cleared of concussion, while rookie scrumhalf Joe Powell will continue to train with the squad as a back-up for White.

SUPER RUGBY ROUND 10

Friday: ACT Brumbies v Otago Highlanders at Canberra Stadium, 7.40pm. TV time: Live on Fox Sports 2. Tickets available from Ticketek.