Toomua also opened up about his doubts on whether he could still perform at the top and his ability to lead a team to the Super Rugby finals after a horror stretch of injuries, including a knee reconstruction last season.

The Brumbies will get a chance to book their place in the Super Rugby final when they play the Pretoria Bulls at Loftus Versfeld on Sunday morning.

For Toomua it's a perfect chance to prove he can handle the big stage and press his claims for a Wallabies jersey.

He will line up against Springboks No.10 Morne Steyn in Pretoria and could then face off with Canterbury Crusaders star Dan Carter in the grand final.

''I never felt I couldn't be a No.10, but it's helped to get some runs on the board,'' Toomua said.

''This is my sixth season, but it's the first where I've played the whole year. I had a lot of doubts coming into this year. You start questioning whether you are good enough.

''Deep down you know you are but you have to prove to yourself and others. I always knew I could play at this level … but you wonder is it me? Is it bad luck? It's nice that's out of the way.

''It was just over thinking because I spent so much time on the sideline.''

Toomua is tipped to challenge Quade Cooper for the Wallabies flyhalf role at the end of the year.

New Test coach Ewen McKenzie is expected to reinstate Cooper, but Toomua has launched an impressive bid to get his first international opportunity. The 23-year-old has benefited from an extended run in the Brumbies' No.10 jersey.

Toomua joined the Brumbies as a teenager and spent six years biding his time behind Christian Lealiifano and Matt Giteau for the chief playmaker role.

He got his chance when White took over as coach. But his first year as the team's flyhalf ended in heartbreak when he busted his knee after just a handful of games.

He has regained his confidence and with the young Brumbies intent on long-term success, Toomua declared his intention to sign a new contract. White has started locking in players long term in the hope of being a championship contender every season.

Toomua's deal finishes at the end of next season, but he said he would not be tempted to leave.

''I'd love to stay in the program and that's the general feeling of most guys,'' he said. ''We are in the semis but we don't even feel like we're at our best.

''I'm happy to play with negotiations going on, but I've never been one to chase deals elsewhere.

''I know where I want to be. Having Jake and Steve [Larkham] are a massive part of that, especially when you want to get better.

''I've been with the club since I was 16. I've always wanted to be in the Brumbies' No.10 jersey. And if I can, I'd love to be here a long time. This is the best place for me to be.''

The bulk of the Brumbies squad has re-signed until the end of 2015 which aligns with the end of White's tenure.

The Brumbies broke a nine-year finals drought when they beat the Free State Cheetahs in Canberra last weekend. Now they are aiming to become the first team to beat the Bulls in Pretoria in a finals match.