But Brumbies coach Stephen Larkham believes players should pick one format rather than try to juggle both. Nevertheless, he has backed Speight to make a successful transition to sevens as he uses the Brumbies' first trial match to give wingers a chance to fill the flying Fijian's shoes while he's on sevens duties.

Speight is set to ignite his Olympic campaign at the sold-out Sydney Sevens this weekend at the same time the Brumbies are playing the NSW Waratahs in a pre-season trial in Wagga.

The 27-year-old winger admitted it was hard to walk away from more than half of a Super Rugby season with the Brumbies as they chase a drought-breaking title.

But the chance to chase a potential Olympic medal later this year was too good too pass up.

"It was very tough to make the choice, and the reality is hitting me that I won't be playing as many games as I would like for the Brumbies," Speight said.

"I'm in contact with the boys every day ... I'm still a part of the Brumbies squad for 2016 and that's all that matters to me. It's a team I've invested in and a team that has really looked after me for the last five years."

Speight is one of three Wallabies players – alongside Quade Cooper and Nick Cummins – to commit to the sevens program, but he is the only one currently on a Super Rugby contract.

The ARU devised a deal for Speight to juggle both duties and he will play in the Brumbies' trial against the Queensland Reds on February 12, less than a week after the blockbuster Sydney Sevens.

Larkham backed his try-scoring speedster to make a smooth transition but added: "Ideally we'd like guys in our program for continuity and the combinations they build over a full season. But some of these decisions are guided by the ARU and in an Olympic year there's focus for success in sevens.

"We understand the situation we're in, Henry is a great Super Rugby player and a great sevens player."

Brumbies including Nigel Ah Wong, James Dargaville, Aidan Toua and Lausii Taliauli have a chance to step up and replace Speight.

"It's just an opportunity, and they've been training well. It's difficult coming in and out of programs and there's a fair difference between sevens and 15-a-side," Larkham said.

"We've got to develop other guys as well, all of the wingers are aware of the situation with Henry and they're all very keen."

Speight will reunite with former coach Andy Friend at the Sydney tournament, almost six years after Friend offered him a deal to move to Canberra to join the Brumbies.

Speight made his sevens debut in Dubai less than a month after being a part of the Wallabies' World Cup campaign.

"Yeah, I guess there's a bit of extra pressure in making that transition over to sevens. And the excitement of the Sydney Sevens is just starting to dawn on us," Speight said.

"There is pressure on the group collectively to do well on our home soil. The good thing is that I've been training with the group since I got back from the World Cup.

"I've done a lot of learning. That doesn't mean I'm perfect at the game – there's a lot of learning to go and I've been soaking up as much as I can.

"Before proving any critics wrong, or the naysayers, the most important thing for us is to earn the respect of the team and play our part."