Cusack has stepped up this season in the absence of Pocock, who has missed eight of 11 games through concussion and a niggling calf injury.

Wallabies star Pocock is not expected to return to Super Rugby after the World Cup in October and Brumbies coach Dan McKellar confirmed he was interested in Waratahs flanker Will Miller.

"Yeah, he's a good footballer, a good player, Miller," McKellar said.

"You've always got to be thinking about the future and if you're not you're going to get yourself into trouble.

"The beauty of myself and the (coaching) staff being renewed and extended means we've got the benefit of thinking where the club is going to be in three years time.

"It's up to David (if he keeps playing) and he'll make that decision and announcement in due course."

Cusack played rugby sevens at the 2016 Rio Olympics and the 26-year-old wants to represent Australia again at the Tokyo 2020 Games.

His new contract will allow him to play sevens in the Super Rugby off-season.

"Tommy is a Canberra boy, he was in our pathways before he went away and played sevens ... now he's back doing a really good job at Super Rugby level," McKellar said.

"He's been one of our most consistent performers of the last couple of years. You ask him to play seven and he'll do a job, you ask him to play six or eight, he never complains, just gets in and does his job."

Brumbies young gun flanker Rob Valetini has already re-signed, while veteran back-rower Lachlan McCaffrey is still negotiating a new deal.

The Brumbies can go top of the Australian conference when they host the Sunwolves on Sunday.

"They're a dangerous team," McKellar said.

"In their first year or two were the easy beats of the competition but that's certainly not the case anymore. They're a quality side that are very well coached and our boys are well aware of that."

Australian Associated Press