Rolland delivered the caution of the tournament start on Friday, telling teams that the number of sin bins and send-offs would be determined by players, rather than officials.

England coach Eddie Jones has been outspoken on the topic, describing as "ridiculous" the red card shown to All Blacks lock Scott Barrett for a dangerous tackle on Wallabies skipper Michael Hooper last month in Perth.

Australian Jones said the sending off "lacked common sense" and was inconsistent with how other similar incidents had been handled this year.

He said a lack of consistency threatened to ruin the global showpiece tournament.

Rolland said player welfare came before everything and noted new guidelines aimed at reducing incidents of concussion had been drawn up in conjunction with leading Test coaches.

"We've made it very clear as to what the high tackle framework is, how it would operate and how it is there to protect them. Everything we do is to protect the players," he said.

"I'd be very confident that they (players) are aware of the high-tackle framework, and how it works."

Under the new instructions, referees must confirm contact to the head, assess the level of danger to player welfare and whether there were mitigating circumstances.

While there had been confusion over the role of the TMOs Rolland said their protocols are unchanged in Japan.

"He's looking at serious acts of foul play, where he can assist match officials. (Otherwise) around grounding (the ball) around try time, there are other things that can be checked - forward passes, obstructions, offside."

Australian Associated Press