Australia boss Michael Cheika said he was "embarrassed" by the decision to penalise Wallabies centre Samu Kerevi following a tackle incident during his team's 29-25 World Cup defeat to Wales.
French referee Romain Poite and the television match official punished Kerevi after a first-half collision with Wales replacement Rhys Patchell, who appeared to catch Kerevi high.
A lengthy television match official review followed and it was decided that Kerevi had made contact with Patchell's throat with his elbow, although it seemed unintentional.
Cheika could not mask his frustration at events after a game that was stopped several times to check the legality of tackles.
It followed Wallabies wing Reece Hodge being cited and banned for a dangerous tackle in Australia's opening group game against Fiji last weekend.
Cheika had already hit out at World Rugby in the wake of that and his latest comments will undoubtedly attract further attention.
Asked for his view after the Patchell-Kerevi incident, Cheika sarcastically said: "It was pretty funny because I thought I had seen that tackle before. It could have been Reece Hodge, I'm not sure.
"Our guy makes that tackle and has the high-tackle framework in his head. He gets suspended, but this guy doesn't think about the high-tackle framework and we get penalised.
"As a rugby player, as a former player, I am embarrassed about that. I don't know the rules anymore.
"You've got to take care, you've got to look after players, but not to an extreme where you are looking after players just for doctors and lawyers. You've got to look after players for players.
"Referees are worried about making wrong decisions and become ultra-cautious. With a crowd like that, there shouldn't be booing, that shouldn't be happening.
"I don't understand anymore. They all seem spooked. Everybody seems worried, they are all worried about stuff so much.
"I am not sure why they are worried, the players aren't worried. Then it's affecting everything else on the field."
Kerevi, meanwhile, was in no mood to hold back either as Australia were left to reflect on a defeat that could see them facing England in the quarter-finals.
"The way rugby is going, I might as well join the NRL next, seeing how they police it," Kerevi said.
"It's a hard decision for the referees, I understand that, I guess I just have to change my technique and the way I run. I respect what the referees decide and I have to move on from that.
"If you slow it down, that slow, it kind of looks like I've been playing like that for my whole career.
"That's the first time I've heard that I can't lead with my arms and bump. It's hard when you slow it down, and in one tenth of a second it seems like I'm on his neck, but I am not.
"There is no malice in it. I apologised to him. The way rugby is going that's just the ruling now. I love my rugby league, so (I might) have a look at NRL.
"This is not a contact sport, this is a collision sport, and if you want to play touch, go play basketball.
"We are here to run straight at people. I've got to be more careful. I felt like I let the team down."