Ange Postecoglou says the proposed introduction of a blue card and sin bin for dissent will "destroy football" and that the game needs to "declutter".
Global governing body FIFA and IFAB, the custodians of the game's laws, said they would discuss punishing certain fouls by sending players off the field at their AGM next month.
The plans were given short shrift by the Tottenham manager though, who joined other Premier Leagues bosses in issuing a stern rebuke to football's lawmakers.
"Adding another [card]. What is that going to do? The remedy is already there," Postecoglou told the BBC.
"If it's not being enforced to the level people are satisfied, do that. That's the change.
"One team being down to 10 men for 10 minutes, you know what that is going to do to our game? It's going to destroy it.
"You'll have one team sitting there trying to waste time for 10 minutes waiting for someone to come back on. Every other game is trying to speed up and declutter, all we are trying to do is go the other way for some bizarre reason."
FIFA said on Thursday that any trials would only take place at the lower levels of the sport, and that the topic would be discussed early next month at the annual meeting of the International Football Association Board.
"Sin bins" were introduced across all levels of the grassroots game in the 2019-20 season in a bid to reduce dissent and increase fair play.
British media reports on Thursday said the use of sin bins could be extended to include tactical fouls — such as when a player takes down an opponent to stop a counterattack.
FIFA though, said reports of the blue card being implemented at elite levels were "incorrect and premature".
"Any such trials, if implemented, should be limited to testing in a responsible manner at lower levels, a position that FIFA intends to reiterate when this agenda item is discussed at the IFAB AGM on 2 March," FIFA said in a statement on X.
Postecolgou said the constant tinkering of the game needed to stop.
"I struggle to understand why [there is] this urgency all of a sudden to bring in new things," Postecoglou told media ahead of his side's Premier League match against Brighton.
"I don't know if there's that much wrong with the game as I see it.
"My biggest issue with the game at the moment is VAR has changed the experience … whatever you are I think it's changed the experience of football.
"I'm assuming that's a means to an end that they think the introduction of technology is going to get us to a better place — I'm yet to be convinced about that."
Postecolgou also said while other sports are working to speed their games up, football appeared to be going the other way, to the detriment of the sport.
"I struggle with this whole taking from other sports," Postecolgou said.
"What I do know about other sports is most of them are trying to introduce rules that will speed up and unclutter their game.
"We're going the other way and I dunno why because that's always been a difference between football and the other sports.
"A football match almost has a life of its own. and within that there's mistakes, there's flaws, there's imperfections, and other sports tend to be able to stop and start without affecting it.
"Most of the other sports that I look across at are trying to speed up their game, make it a better spectacle. I don't know why we're trying to go the other way."
Postecolgou was not alone in slamming the ideas.
Liverpool boss Jurgen Klopp said the proposed change "doesn't sound like a fantastic idea" while Newcastle boss Eddie Howe said he was "not a big fan".
"That's what yellow cards are for," the Newcastle boss told media on Friday.
"Adding a blue card would just add more confusion, in my opinion."
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