The Scottish Premier League and the Scottish Football League have agreed in principle to a restructuring plan that would see the organisations merge in a 12-12-18 structure.
A vote on the proposals is likely to take place later this month and, if approved, could come into effect as early as next season.
That would mean Rangers remaining in the bottom tier of Scottish football for a second consecutive season, even if they win the Irn-Bru Third Division title.
The potential time frame for a return to the top flight would remain the same, but McCoist is furious with plans to "move the goal posts".
He said: "I don't think the league reconstruction can go through. There is a complete lack of sporting integrity.
"I think the vast majority of the footballing public - the fans included - are probably in agreement that we need change, but you can't have change during a season.
"You can't move goal posts and effectively waste people's seasons.
"If it goes ahead and starts next season, this season is meaningless for a lot of teams.
"There would be no point. What a slap in the face that would be to everybody in SFL3, including our fans and players."
McCoist, who has been named Irn-Bru Third Division manager of the month for December, added: "Our supporters have been slapped right on the coupon at every opportunity.
"It's unbelievable. But all it will do is make them stronger, I know it will. It will make us all stronger.
"This isn't a strop or throwing the toys out of the pram. I just feel, again, if it goes through, it will be another slap in the face to our supporters."
As associate members of the SFL, Rangers have no vote on the issue, but McCoist expected his club to at least be consulted.
He said: "Everybody will tell us the rules are the rules, that we gave that [vote] up for four years.
"It wouldn't happen in any other country. You would ask the opinions of the top team in the country in any other country in the world.
"But we don't have a right of complaint because seemingly we are not entitled to an opinion because we have given that up.
"It's kind of small-minded if you ask me but it's fine, I don't have a problem with it because that's the rules."
McCoist revealed the uncertainty over next season has resulted in Australian goalkeeper Mat Ryan scrapping a trial which was set to take place next week.
A transfer embargo means the Gers boss must wait until September to register free agents - and January 2014 to buy players - but he can secure targets on pre-contract agreement this month.
He said: "Mat's unaware of what league we are playing in.
"He must be sitting shaking his Australian head and wondering what's going on. That's where we are.
"I spent months not being sure what league we would be playing in and it seems we are going to get the same again this summer.
"We are trying to get players who are out of contract in the summer, with the possibility of registering them on September 1.
"The first question they are going to ask is 'Right, what league are we in?' 'I can't tell you that but I'll get back to you.'
"Which is where we were last year. You couldn't make it up."