But the flying Fijian has vowed to continue his mission to repay the Brumbies for giving him a Super Rugby chance, declaring "I'm a Canberran" and that he is desperate to score on Saturday night.

Speight will play his 50th game for the Brumbies in the Australian conference blockbuster at Canberra Stadium.

It is a milestone Speight thought he would never reach when no Super Rugby team was willing to give him a chance – until the Brumbies offered him a contract.

The Brumbies and Waratahs share a rich history of hatred, stretching back before Super Rugby started in 1996.

''As an outsider coming here, I knew nothing about the [Brumbies' hate for the Waratahs],'' Speight said.

''Then in my first 'Tah Week', first thing on Monday morning you get guys freakin' screaming in your ears that it's Tah Week.

''I was thinking, 'what the hell is happening here'. But I've come to appreciate how important these derbies are, what it means to the team and to Canberra. I'm deadset on Tah Week as well, I'm a Canberran.''

Speight was the top try-scorer in Australia last season, but has failed to cross the line in three games this year.

The Brumbies' cult hero has scored three tries in his past four games against the Waratahs and hopes he can open his account this week.

The Brumbies signed Speight for the 2011 campaign after star centre Christian Lealiifano spotted him playing in the New Zealand provincial competition with Waikato.

The Fijian-born speedster will be eligible to play for the Wallabies in September.

The International Rugby Board delayed his Australian Test eligibility because of a brief return to New Zealand to play for Waikato, despite Speight being based in Canberra for four years.

''He's played 50 games for the Brumbies but he's still not eligible to play for Australia ... it's a bit ironic. We're lucky to have him,'' Brumbies coach Stephen Larkham said.

The Brumbies have won their past two games and the Waratahs started their season with back-to-back bonus-point wins.

''You have to be careful how you build up a game, you don't want to come in with too much anticipation and lose energy worrying about the game,'' Larkham said.

''We learnt a lot from the [Super Rugby final] last year and guys know how to approach big games now.''