Star playmaker Toomua signed a new three-year deal on Wednesday, making him the only Brumby to commit to a contract beyond next year's World Cup.

Scrumhalf White is poised to join him on Thursday when he signs a two-year contract with the Brumbies and ARU.

The duo's decision to stay in Canberra is a major boost for the Brumbies ahead of Saturday's top-of-the-table clash against Jake White's Durban Sharks at Canberra Stadium.

Inside centre Christian Lealiifano is still weighing up offers from Europe, but is getting closer to a new deal with the Brumbies and has assured management he would not play for another Australian club.

The Brumbies are also negotiating with Scott Fardy, Scott Sio, Jesse Mogg and Joseph Tomane as they work to hold on to a star-studded playing roster.

Toomua announced on Wednesday he was staying in Australia to chase his World Cup dream and aim for a title with the Brumbies.

The talented 24-year-old turned down offers from the Melbourne Rebels to continue working with Brumbies coach and Wallabies great Stephen Larkham.

Larkham believes Toomua can become one of the greatest playmakers in world rugby.

Toomua was a teenager when he was recruited by the Brumbies in 2007.

"This deal will take me to a decade at the club and that is something really special to me, and I'm quite proud of it," Toomua said.

"I'm pretty relieved and happy it's all sorted. I definitely entertained the idea of moving to Melbourne, but I'm very happy with staying with the Brumbies.

"I know the players, coaches and program in Canberra, and I believe I can grow here.

"I want to play for the Wallabies for as long as I can. I'd love to continue doing that if I get the opportunity. I just don't feel right now is the right time for me to look at overseas."

White will sign his contract on Thursday afternoon as the Brumbies and ARU finalise a deal for the feisty scrumhalf.

White's long-term future in Australia will largely depend on the movements of incumbent Wallabies No. 9 Will Genia.

White is pushing Genia for a starting spot in the Test side.

Both White and Toomua made their Test debut last year after guiding the Brumbies into the Super Rugby final.

Their combination was instrumental in the Brumbies successful campaign, and if the club can secure Lealiifano it will lock in key back-line players.

World Cup-winning flyhalf Larkham, who played more than 100 Tests and Super Rugby games, said Toomua was ahead of Quade Cooper in the running for the Wallabies No. 10 jersey.

The Wallabies play France in a three-Test series in June and Larkham said Toomua was "the man for the job" ahead of enigmatic playmaker Cooper.

"[Toomua's] already regarded as one of the best flyhalves in world rugby and a guy like that staying in Canberra gives a lot of other guys confidence," Larkham said.

"I think he's playing some outstanding football at the moment. He's controlling the game well ... he's definitely the best defending five-eighth in world rugby and that puts him one step ahead of Quade.

"I'm being a little bit biased because he plays for the Brumbies, but I genuinely feel his game is suited for Test-match rugby."