Martin O'Neill is of the view VAR [video assistant referee] is "debilitating" for officials on the pitch as he branded the Scottish FA process for appealing against decisions "worthless".
On Tuesday, Celtic lost their bid to have Auston Trusty's red card against Hibernian overturned.
A club statement was critical of the ruling and called for an urgent review of VAR use, complaining that "VAR again decided to intervene to 're-referee' an initial decision".
Trusty was dismissed after a review of his chop on the arm of Jamie McGrath, while the pair tussled at a corner kick, leaving veteran manager O'Neill perplexed.
"I did the interview after the game and someone asked me if we were going to appeal it and I thought I'm really not sure about it, the appeals in this day and age are seemingly worthless," he said.
"But when I get the info back from the club at what has been said in VAR I thought yeah, absolutely, because the referee has seen the incident, it's not like he hasn't seen it.
"And then you've got a very excited man on VAR saying 'delay, delay, delay' and they ask him and he says he's going to have a word with the players.
"Then he has to trot over to change his mind. It's ridiculous."
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O'Neill, in Germany for the second leg of their Europa League play-off with Stuttgart, added: "All I'm saying is that VAR, in time, we won't need a referee.
"VAR will do it for them from wherever they're doing it from because that's what they do.
"They've asked the referee to go over something that he's actually seen. He's seen it, it's not like he's missed the incident.
"He'd said it was nothing, 'I'm going to have a word with the guys'. I've now got a player who is going to miss three games."
Asked if he agreed with the notion of VAR officials re-refereeing matches, O'Neill replied: "Of course they are. It's such a nonsense.
"It's fine if they've missed something dramatic and it constitutes something that they need to have a look at.
"But when a referee sees the incident themself, what he's being told is 'no you didn't see that incident, you didn't see that, you saw something else,' that's got to be debilitating for the referee, it's got to be."