With a backdrop of controversy over the growing influence of the video referee, Gardner was the youngest - and only Australian - referee selected to blow the whistle in the first round of finals matches this weekend.

He oversaw the Waratahs' final round loss to the Brumbies last week and, interestingly, sent a Highlanders player to the bin in their 17-0 quarter-final loss to the Crusaders last year. Gardner is Australia's best referee and considered one of the best young whistle-blowers in the international game. Coach Daryl Gibson said NSW were "very happy" to have him in charge for their knock-out game against the New Zealand visitors at Allianz Stadium.

"SANZAAR have gone through an exhaustive process to find the best referees and have settled on their final four," Gibson said. "Angus has been consistent all year, we were very happy with his performance last week, and I think it's good that there's an Australian referee represented in the final four."

Fans will be hoping SANZAAR's recently announced review of TMO protocols will prevent a repeat this weekend of the anti-climactic intervention that blighted the series decider between Australia and Ireland at the same ground last month.

In the final minute of the match, with the scores at 20-16 to Ireland, the TMO spent several more minutes agonising over a possible intervention in Australia's favour. It turned a heart-stopping battle into a fizzer and was no doubt one of the moments SANZAAR will look at in its review.

Gibson welcomed the move and said he hoped it would put more control back in the hands of the man in the middle of the action.

"There's a balance there between how much the TMO is involved in the game and who rule's who," he said.

"Is the TMO the sole judge or is it the referee? Once we determine those factors, we're going to get an outcome on the field where the referee should be the sole judge of what happens."

New Zealanders Mike Fraser and Glen Jackson, and South African Jaco Peyper, will run the other quarter-finals.

Meanwhile, both the Waratahs and Highlanders named their best line-ups ahead of Saturday's match. Gibson made one change to the Waratahs, swapping Glen Innes winger Alex Newsome in for Cam Clark, who will come off the bench.

"Alex has been really impressive in the last three games in terms of his impact off the bench and he really deserves a start," Gibson said.

"Every time he's touched the ball he's added something ... He's got some excellent wingers he's going to be up against and we know he can do the job."

The Highlanders, meanwhile, welcomed back six players who were rested last week, including star backs Aaron Smith, Ben Smith and Rob Thompson, and forwards Luke Whitelock, Ash Dixon and Elliot Dixon.

Gibson said the match would be a showdown for the ages.

"Both teams have got x-factor all over the place, [and] are littered with blokes who just want to work hard," he said.

"There's a lot of 'no frills' about the Highlanders and our forward pack, so I think it's a really evenly matched game. Both teams like to play positive rugby, so it's going to be an interesting spectacle."

The Waratahs are wary of their opponents' launching a few surprises, calling the Aaron Mauger-coached side a "clever" team with an obvious love of unstructured play.

"I think both teams will see opportunity in each other. The Highlanders are a very clever team, they're always trying different stuff and they're very exciting to watch," Gibson said.

"A lot of our preparation is around how do we prevent that? We've got to make sure our defence is solid and that we don't concede tries as well."

Waratahs squad: Israel Folau, Alex Newsome, Curtis Rona, Kurtley Beale, Taqele Naiyaravoro, Bernard Foley (c), Nick Phipps, Michael Wells, Will Miller, Ned Hanigan, Rob Simmons, Jed Holloway, Sekope Kepu, Damien Fitzpatrick, Tom Robertson. Replacements: Tolu Latu, Harry Johnson-Holmes, Paddy Ryan, Tom Staniforth, Brad Wilkin, Jake Gordon, Cam Clark, Bryce Hegarty.