Players could be shown a blue card for dissent or blatant tactical fouls and would have to spend 10 minutes off the pitch, while two blue cards or a blue and a yellow would result in a sending off.
Postecoglou says there is already a solution for dissent - yellow and red cards - and believes sin-bins will ruin the quality of matches.
“There’s a remedy for [dissent] already: show a yellow card or send someone off - it’s there in the rules,” the Australian said.
“How much [dissent] you tolerate is really up to you. Adding another [card], what’s that going to do? Is it degree of dissent? Or is it any dissent or magnitude of dissent? Is it what you say or what you do? The remedy is already there.
“If it’s not being enforced to the level at which people are satisfied, then do that. That’s the change you need to make.
“I’m in a different space with where I think football’s at. But one team being down to 10 men for 10 minutes, you know what it’s going to do to our game?
“It’s going to destroy it, mate. You’re going to have one team just sitting there trying to waste time for 10 minutes waiting for a guy to come on."
Rugby is among the sports which already use sin-bins but Postecoglou is not convinced of the merits of borrowing from other codes and believes football is "going the other way" to the rest of the sporting world.
“I struggle to understand why this urgency all of a sudden to bring in new things," he continued.
“I don't know if there's that much wrong with the game as I see it. My biggest issue with the game right now is that VAR has changed the experience, whether you're a player, a manager or a supporter. I think it's changed the experience of football.
“I assume that's a means to an end, that the introduction of technology is going to get us to a better place. I remain to be convinced about that.
“Beyond that, I don't know why a different colour card is going to make any difference. I struggle with this whole taking from other sports. What I do know about other sports is that most of them are trying to introduce rules to speed up and un-clutter their game.
“We're going the other way and I don't know why. That's always been the difference with football compared to other sports. Football always has a life of its own. And within that there's mistakes, there's flaws and imperfections.
“Other sports tend to be able to stop and start and stop and start without affecting it. Even in that, most sports I look at are trying to speed up their game and make it a better spectacle. I don't know why we're trying to go the other way.
"I guarantee though that I won't be in the room when they're making those decisions."
IFAB, the International Football Association Board, is made up of the Football Associations of England, Scotland, Wales and Northern Ireland, and world governing body FIFA.
Postecoglou says it is down to "the custodians" of football "to protect the game" but questioned who exactly is pushing through so many rule changes.
“I’ve always loved the fact that our game has remained untouched from my 40 years in it”
“I assume the governing bodies are the custodians at the moment, but what I’m talking about is the detail of it," he said.
“When, for want of a better word, change presents itself, who is representing the game and are we getting enough of a cross-section of who we need to be?
“If you’re asking me how it currently works, I’ve got no idea, mate. I haven’t been in that space and dare I say it, I never will be. When I talk about those things, I’m just talking as a fan of the game. That’s all I’m saying.
“As a fan of the game, I’ve always loved the fact that for the most part our game has remained untouched from my 40 years’ experience in it.
“There have been some rule changes. I remember when I was playing I could pass it back to my goalkeeper and he could pick it up and throw it back to me and I’d pass it back to him and he’d pick it up again. You know what, they changed it. Why? Because they didn’t want to see the game slowing down, so it was a good decision. Let’s go with it and I don’t think anyone has complained about it.
“Other than that, there haven’t been too many shifts, but all of a sudden we’ve seen such a major transformation. We’ve let technology in the door, we know that’s going to affect it. Let’s just see how that plays out before we start thinking about other significant changes.
“What I guess I’m saying is, the conversation we’re having now, who is having those conversations? I don’t know."