Powell will go head to head with former Brumby Tomas Cubelli in a Super Rugby semi-final in Buenos Aires on Saturday morning.

It's a chance for Powell to enhance his Wallabies selection credentials against an international No. 9 after falling off the Test radar in the past 18 months.

But the looming Australian rugby comeback of Nic White has clouded the Wallabies' scrumhalf picture for the World Cup, despite Powell finding his best form this year.

The clash against the Argentina Jaguares is an opportunity to show how far he's come since being White's understudy in 2015 and Cubelli's back-up for two years.

Another impressive performance would fire a timely reminder to Wallabies coach Michael Cheika, who dropped Powell from the spring tour squad last year.

The Brumbies have been the standout Australian side this year and team success can boost the international hopes of several fringe Wallabies, including Powell, Tom Banks, Henry Speight and Toni Pulu.

That's why Powell is itching to land a blow against 69-Test veteran Cubelli to keep alive the Brumbies' hopes of ending a 15-year championship drought.

BRUMBIES NEWS

"I'm looking forward to it, I love playing against Tomas. He was great for the Brumbies when he was [in Canberra] and all the boys like him, but I'm sure we're ready to whack him as well," Powell grinned.

"The way he runs the ball and backs himself on the field, he's got that flair about him and he'll try anything, he definitely helped me out with those sorts of things."

The Brumbies have put individual Wallabies ambitions on the back-burner to focus on their daunting Argentinean task this weekend.

The Jaguares have won 10 of their past 11 matches and have beaten the Brumbies in the past two matches between the clubs.

Cubelli threatens to be a thorn in the Brumbies' side after making a successful comeback from a fractured vertebrae this season.

The Brumbies, however, are riding their own wave of form through the play-offs after winning seven games in a row to set a record for the longest single-season winning streak in the club's history.

Powell is one of only four Brumbies to have played every game this season, joining Christian Lealiifano, Banks and James Slipper. All four are trying to launch their respective Wallabies careers.

Powell has played just four Tests since making his debut two years ago after being overlooked by Cheika, who has favoured Will Genia, Nick Phipps and Jake Gordon.

White's has signed an Australian rugby contract, making him eligible for Wallabies selection and adding another hurdle for Powell's Test ambitions.

White will likely join the Brumbies from the end of 2020, but the Melbourne Rebels have also shown interest in the 29-year-old.

Lealiifano hasn't played a Test since being diagnosed with leukaemia in 2016, Banks is one of the leading candidates to be Australia's fullback replacement for Israel Folau and Slipper has resurrected his career in Canberra after a controversial end to his Queensland playing days.

"To be honest we haven't really been thinking too far ahead," Powell said.

"Those things [winning Super Rugby] are in the back of everyone's mind and we obviously want to do it, so we'll see what happens from here.

"There's a really good feeling around the place at the moment. I can't put my finger on it, we went through some tough times at the start of the season but we're reaping the rewards of hard work."

The Brumbies are expected to make minimal changes to their side this week, with Lachlan McCaffrey the likely candidate to replace Pete Samu (hamstring) in the starting side.

SUPER RUGBY SEMI-FINAL

Saturday: Argentina Jaguares v ACT Brumbies at Jose Amalfitani Stadium, Buenos Aires, 9.05am (AEST).