His clearance had not yet come through this morning but Poverty Bay Rugby Football Union chief executive Josh Willoughby was confident he would be allowed to play.
Cairns said Waaka had a “massive skill set” and he would be vocal at the back.
Andrew Tauatevalu is set to move to the left wing, with Matt Raleigh going to the substitutes bench.
Poverty Bay will be without their best player from the opening weeks of the competition — openside flanker Adrian Wyrill has been ruled out with a leg injury.
Blindside flanker Quade Tapsell — Poverty Bay’s player of the day last week — is also out with a toe injury.
Cairns, however, is confident the players called up in their place can get the job done.
OBM loose forward Nicolas Carrizo is set to team up with clubmate Morgan Reedy as the two flankers, with Tamanui Hill, from High School Old Boys, again at No.8.
Wairarapa Bush have had injury troubles but they’re unlikely to struggle with the pace of the game.
They’re used to playing on the artificial turf, which their coach says promotes running rugby.
Cairns thinks the turf will also suit his side, though the players will need to make some adjustments, such as allowing for the ball to bounce higher than it normally would.
Wairarapa Bush had a 37-31 win against King Country last week and are sixth on the points table. King Country had three players sin-binned and were down to 13 men at one point but still got close.
Poverty Bay are eighth on the ladder and have had one win but they’ve had a rough early draw and if they play as well as they did against North Otago, they will pick up more wins this year.
Wairarapa Bush coach Joe Harwood said both teams loved to throw the ball around.
“I don’t think it will be a low-scoring game,” he said.
“Both teams will give it a nudge.
“I expect a fast game. The turf always allows for running rugby.”
Harwood described his squad as injury-ravaged and said players from the Development team and a couple of veterans had to be called in.
They should know each other quite well, though.
Four of the side are brothers — prop Max, reserve prop Sam, No.8 and captain Kirk, and centre Ueta.
Tristan Flutey, who scored two tries last week, is on the left wing and his brother Logan Flutey is in the reserves.
Poverty Bay captain Ken Houkamau said he had played on the turf before and it was a good surface.
He said the team made significant strides forward last week, culminating in a strong showing against North Otago.
“We are training well and hoping to carry on momentum from last week.”
It’s not just Heartland points that are at stake.
The Jeremy David Memorial Cup, which the two unions contest and which Poverty Bay have held since 2017, is again on the line.
Nick Webster will referee the match.
WAIRARAPA BUSH: Inia Katia, Tim Priest, Ueta Tufuga, Brock Price, Tristan Flutey, Tipene Haira, Daryl Pickering, Kirk Tufuga (c), Brendon Campbell, Andrew McLean, Lachie McFadzean, Max Tufuga, Bruce Kauika-Petersen, Sam Gammie.
Reserves: Elijah-James Pakoti, Sam Tufuga, Brent Wilson, Logan Flutey, Bryan Arnold, Cameron Hayton, Alex Priest.
POVERTY BAY: Beaudein Waaka, Scotty McKinley, Ethine Reeves, Andrew Tauatevalu, Tane McGuire, Willy Grogan, Tamanui Hill, Nicolas Carrizo, Morgan Reedy, Gabe Te Kani, Ken Houkamau (c), Semisi Akana, Rikki Terekia, Toru Noanoa.
Reserves: Matekaeroa McGuire, Lance Dickson, Juston Allen, Will Bolingford, Mario Counsell, Kelvin Smith, Matt Raleigh.