AAP

The free-scoring Brumbies are looking forward to a massive clash with the NSW Waratahs after completing one of their best Super Rugby campaigns in South Africa and extending their lead in the Australian conference.

A six-tries-to-two 34-20 win over the Lions in Johannesburg on Saturday morning (AEST) ensured the surprise packet frontrunners stayed ahead of the chasing domestic pack.

The victory lifted them six points clear of both the Queensland Reds and NSW, though the Waratahs can make up ground with a home win over the Crusaders on Sunday.

The Brumbies scored three tries in each half and would have won even more convincingly had kickers Christian Lealiifano and Jesse Mogg not missed six of their eight combined shots at goal.

The visitors trailed 6-5 in the first half following two penalties to Lions five-eighth Elton Jantjes, but the Brumbies then piled up 29 unanswered points.

The Brumbies will return home with a haul of seven points, their best effort in South Africa for five years.

It was the third straight game they earned a coveted tryscoring bonus point and ensured South African-born former Springboks coach and current Brumbies mentor Jake White had a happy homecoming.

"We've scored five, five and six - 16 tries in three weeks - it's phenomenal," White told AAP from Johannesburg.

"You've got to compliment (Brumbies backs coach) Stephen Larkham.

"We lost (five-eighth) Matt Toomua (to injury) and yet our backs are still scoring tries."

White reported no injuries and said captain Ben Mowen should be back for the vital home clash with the Waratahs next Saturday.

"It's going to be a massive, massive game for us," hooker and stand-in Brumbies skipper Stephen Moore told AAP.

Sparked by dangerous five-eighth Lealiifano and lively back-rowers Michael Hooper and Foto Auelua, the Brumbies were far too clinical for the mistake-ridden Lions.

They capitalised on turnovers and many missed tackles, consistently hurting the Lions out wide.

The Brumbies led 17-6 at the break, following tries to prop Ruaidhri Murphy, winger Henry Speight and centre Andrew Smith, but missed kicks worth 10 points, with Lealiifano also butchering a try by dropping the ball over the line in a tackle.

Tries to winger Joseph Tomane and Ben Alexander early in the second half put the Brumbies well clear and Speight crossed for his second just before the hour mark.

Centre Jaco Taute and prop Caylib Oosthuizen earned the well-beaten Lions a scrap of respectability with last-quarter tries.

The Brumbies didn't add to their score in the final quarter despite Lions reserve back Butch James earning a yellow card for a shoulder charge on lock Scott Fardy, which resulted in the Springbok back being cited for alleged foul play.