Staniforth is heading up the Hume Highway to join the NSW Waratahs, having been stuck behind a number of world-class locks in Canberra.

Canberra-born flanker Cusack follows Nic Mayhew and Les Leulua'aili'i-Makin in putting pen to paper with the Australian conference leaders, signing on for another two seasons.

Staniforth's departure brings an end to his four-year tenure at the Brumbies and Cusack says losing such a great club man is a cruel blow.

"I've played a lot of footy with Tommy over the last couple of years. He's a quality footballer and it's a shame to see him leave the Brumbies frame," Cusack said.

"He's going to be one bloke that's going to be missed. I've always spoken very highly of him and he's a character on and off the field so someone is going to have some big boots to fill there.

"He's one of those blokes that you love to play with, an aggressor on the field and a smart head as well."

Competition for lock spots at Brumbies headquarters is fierce and Cusack backed Staniforth to play regular Super Rugby in sky blue.

Cusack represented Australia at the Olympic Games in sevens rugby and believes Staniforth can show his own versatility in filling a number of positions for the Waratahs.

"With key players leaving over the next couple of months for the Tahs, he's a versatile player so I feel like he can play anywhere," Cusack said.

"They're going to be looking for someone with a bit of experience and he's someone that brings that. He's played a number of games down here so I think it's a good fit for them up there, although it's disappointing for him to leave us down here."

The Brumbies are moving to re-sign a host of key players after the ARU lifted a contract ban and Cusack is glad to have moved past the "complete unknown" that many Super Rugby players are still battling.

"While you had the Brumbies being ruled out of the equation somewhat early, it still had the whole impact of the fact that there's going to be 30 blokes coming on to the market," Cusack said.

"You still had that to contend with, and getting your mind around that situation and getting into negotiations pretty quickly, it kind of put your mind at ease."

Cusack says the pair will relish every moment they get to play together for Canberra club Royals this season, but he maintains the pair will cross paths in the same team down the track.