Sydney - Red cards meted out as part of a crackdown on concussion-related injuries are here to stay, World Rugby chief Brett Gosper said on Sunday, despite frustration over recent decisions.
Leicester interim head coach Geordan Murphy said last week the "game's gone too PC" after lock Will Spencer was red carded for catching hooker Tommy Taylor with a shoulder to the head.
Earlier this month, Australia's George Smith, a flank with Bristol, was sent off for a dangerous tackle against Saracens that was later rescinded by a disciplinary hearing.
"We've got to work on our consistency I guess, but at the end of the day we're trying to change player behaviour," Gosper told reporters ahead of World Rugby meetings in Sydney, where the sport's top body will discuss numerous issues facing the game.
"We're trying to lower the tackle height so we can reduce the incidence of concussion and injury... and cards are the best way to change player behaviour."
He added officials were already instructed to look out for neck rolls, despite calls from the Wallabies for officials to take more action amid accusations All Blacks players were targeting star flanker David Pocock.
Pocock was ruled out of Australia's clash against the Springboks this month with a neck problem.
"I can't comment on any one incident but we're certainly against neck rolls and the laws are against neck rolls and people are instructed to look out for that sort of behaviour," Gosper said.
Amid disquiet about Super Rugby's video refereeing system TMO (television match official), Gosper added that there could be changes after governing body SANZAAR ordered a review in July.
Coaches and pundits have expressed concerns the TMO was becoming increasingly influential and undermining the on-field referee.
"We had a working group looking at that, they'll report into the rugby committee this week so we can't share the results of that because rugby committee haven't discussed it yet," he said.
"I think there will be some positive change but I can't pre-empt that until those discussions are had."