Brian O'Driscoll has appealed to World Rugby to address the "blight on the game" of slide tackles.
The Ireland legend and BT Sport pundit is disappointed by referees' ignoring illegal tackles such as Castres fly-half Benjamín Urdapilleta's knees-first hit before Andrew Conway's disallowed try.
Referee Wayne Barnes was criticised for his role in Munster's controversial defeat on Saturday and O'Driscoll highlighted an overlooked decision from Barnes' performance.
"It's clear that Conway does knock the ball on but look at that for leading knees," said O'Driscoll.
"It's something that needs to be stamped out of the game and I'm disappointed to see that referees are allowing that go.
"It's not football, you can't have a slide tackle!"
"World Rugby need to stamp down on that, it's a blight on the game."
In a game with many moments of questionable play...
Brian O'Driscoll feels Munster were very hard done regarding this Andrew Conway disallowed try. pic.twitter.com/hw2emTpPP3— Rugby on BT Sport (@btsportrugby) December 16, 2018
"I'm really disappointed because Conway missed the summer tour in Australia because of a similar knee drop.
"He's even not trying to go for it with his arms. I don't think it's a penalty try because I don't think you can guarantee that Conway is going to pick that up and score but it's absolutely a yellow card.
"EPCR [European Professional Club Rugby] and World Rugby need to stamp down on that because it's a blight on the game."
Meanwhile, former Munster star Alan Quinlan believes his old team's controversial Champions Cup defeat to Castres was "a disgraceful throwback to the nineties".