There is a new call for the Leaving Certificate to be abolished, with radical reform of access to third-level education.
A motion from People Before Profit will be debated in the Dáil on Thursday.
Dún Laoghaire TD Richard Boyd Barrett told Newstalk Breakfast there should be no limitations.
"I think the Leaving Cert crisis we've had under COVID has really highlighted problems that pre-existed COVID with the Leaving Cert and with access to higher education.
"The enormous stress that people are suffering, the intense competition to get places - and it really begs the question: why are we limiting or rationing access to higher education?"
He said the "winner takes all" system is a one size fits all solution, which Deputy Boyd Barrett compared to limiting access to secondary education.
"We wouldn't even dream now of rationing access to secondary education, it would just make no sense for our society - although once upon a time we did do that.
"Why are we doing it now when we desperately need qualified, educated people in a whole range of areas?"
Deputy Boyd-Barrett said the hierarchical system has to be replaced.
"Part of what the Leaving Cert does, and indeed the fees structure and all that, is create a hierarchy in the idea what further education and higher education is - and we need to remove that as well.
Asked if people being taxed to pay for graduates education was fair, he replied: "Anybody who we put the investment in at any level of education pays that investment back to our society many, many times over.
"In fact, to be honest, the people who probably end up costing society more are the people who are denied access to higher education because of the damage it does to them and their personal development".
'A gateway you either get through or don't'
Host Ciara Kelly suggested there still needs to be some kind of certification at the end of secondary school, for those who may not want to progress to third-level.
Deputy Barrett said: "It may well be the case that some sort of certification would be useful, but I think in truth we know that the Leaving Cert is a hurdle, an obstacle, a gateway that you either get through or don't get through".
Asked how it is decided who gets into which course, Deputy Barrett said people should be able to try different options.
Citing an example of a GP he spoke to, he said: "I was talking to a GP who qualified in medicine in the '60s in UCD, and he pointed out there was no barrier to doing medicine in the 1960s.
"He pointed out there was a thing called pre-med... his point was there was no limit to people going in and trying medicine.
"This is true in a lot of other countries, by the way, that people can go into the courses or apprenticeships.
"We also limit the numbers of apprenticeships in this country, the number of people going into nursing - it's crazy - when we need these people.
"So why would we put an unnecessary barrier - whether it's an exam barrier or a financial barrier".