World Rugby's crackdown on high tackles has moved too quickly for the World Cup and officials could end up hurting the "show business" of the tournament with inconsistent decisions, according to Australia director of rugby Scott Johnson.
All Black Scott Barrett was given a red card for a high tackle on Wallabies captain Michael Hooper during Australia's 47-26 win in Perth on Saturday and the lock was subsequently banned for three weeks.
Referee Jerome Garces' decision, which left the All Blacks with 14 men after halftime, was labelled "ridiculous" by England coach Eddie Jones, while Wallabies boss Michael Cheika could only offer qualified support despite his team being the beneficiaries.
World Rugby issued new guidelines on penalising head-high tackles in May in an attempt to produce more consistent decision-making but referees must still exercise a level of discretion when judging degrees of "danger".
"There's general concern because there's a major change, a seismic shift really in the way the game's played and certainly the height at which the game's expected to be played at," Johnson, who is also on the Wallabies selections panel, told a Fox Sports podcast.
"It is difficult for very big men to get that low but I understand the reasoning.
"It's about safety, I have a personal view of it, I think we've probably moved a little quick for the tournament. It's for us as administrators to argue appropriately, in different forums, for what we think is the best interests of the game, moving forward.
"Because at the end of the day we are in show business and we want to make sure that what we put out on show is a product worth watching."
Wallabies lock Rory Arnold said it was tough for big men to get low in the tackle and they would need to work harder not to stray on the wrong side of the rule.
"I've always copped a few penalties here and there for high tackles and I've got to watch out and got to drop my hips and stay a bit lower there, but I'm always thinking about it," he told reporters in Melbourne.
"It's different for tall fellows."