Because Scott Sio and the Brumbies' all-Wallaby front row are adamant their set piece has to take a major step if they are to be considered genuine favourites to claim the Super Rugby AU title.

The visitors will enter as raging hot favourites when they face the NSW Waratahs at Sydney Olympic Park on Saturday night.

But Sio says even the slightest hint of ill-discipline could be a cruel blow for the Brumbies as they set their sights on a return to the top of the table in a cross-border grudge match.

Six scrum penalties in their opening round win over Melbourne left captain Allan Alaalatoa frustrated and it is something the Brumbies pack - led by Alaalatoa, Sio, Folau Fainga'a and James Slipper - is desperate to address.

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"It's just consistency, that's what it is after three or four months. Certain parts of the game were a bit rusty," Sio said.

"With the lead we had built, if you want to win this competition, you have to be able to continue on and keep building scoreboard pressure there.

"We know our set piece needs to take another step up if we want to be a real contender for this title. We put in some good work on Monday and Tuesday, and having these couple of days here will help us refresh and have us ready to take on the Waratahs.

"We went back and had a good review on Monday and Tuesday about where we can get better and how we can grow as a team, so when we run out against the Waratahs, we're making all the right decisions at the right time.

"It was just great to be back out there with the crowd [in round one]. You could see there was a bit more of a buzz around town, also having the Raiders back at home as well, it's great for Canberra and our community."

The clash marks the Waratahs' first match at Sydney Olympic Park since 2015 following the NSW government's decision to halt refurbishments planned for the stadium, with the club living something of a nomadic existence in recent years.

Early discussions had the 83,500-seat venue pencilled in to hold about 5000 spectators as sports slowly welcome crowds back following the COVID-19 shutdown. However that figure could change pending NSW government restrictions.

"We are playing at [Sydney Olympic Park] which is just up the road from where I grew up, so it's always pretty special to have my family at the game," Sio said.

"I'd love to have them there. If not, we've just got abide by the COVID protocols and hopefully keep this competition going."