Sinn Féin's housing spokesperson Eoin Ó Broin says there needs to be a three-year ban on rent increases.
He says plans by the Government, linking rent increases to inflation, do not go far enough.
Cabinet has approved the new rules which will replace the current annual 4% increase allowed under Rent Pressure Zone (RPZ) legislation.
Moving forward, RPZ increases can be no higher than the general inflation recorded in the Harmonised Index of Consumer Prices (HICP) – which currently stands at just under 2%.
But Deputy Ó Broin told The Hard Shoulder the situation is too far gone for many.
"I tabled legislation to do precisely this back in 2016.
"And if Fianna Fáil and Fine Gael hadn't have opposed it back then, in fact rents wouldn't be where they are today.
"It was absolutely the right policy at the very start of the kind of upward trajectory of rents.
"The difficulty I have is is that we're now in a situation where large numbers of renters have experienced rent increases of between 20% to 30% over the last four years - notwithstanding the Rent Pressure Zones.
"Dublin is particularly acute, but we've seen over COVID even outside of the cities double-digit rental increases."
Deputy Ó Broin says not all landlords stuck to the rules.
"What should have happened is you should have been constrained to 4% annually - that's over four years - that should be 16%.
"But for example: for new rents, if you look at the Daft.ie quarterly reports, but also new and existing rent - if you look at the Residential Tenancies Board quarterly reports - you're looking at rents between 20% and 30% increases over that period of time.
"There are some renters whose landlords have respected and stayed within the Rent Pressure Zones, but many many haven't.
"What that means is today an average renter, according to the official figures, is paying between €4,000 and €6,000 more a year than when I introduced the rent certainty legislation .
"It means we have to stop rent increasing for an emergency period.
"Therefore what's actually required now is not linking rents to inflation, it's a three-year ban on rent increases for new and existing tenancies.
"And then after that period, when some other interventions in the rental market have helped stabilise it, then you would move towards linking inflation.
"But right now, renters cannot take any increase".
He says even under the existing inflation plan, prices will still go up.
"Inflation for example this year is 1.9% - and clearly 1.9% is better than 4%.
"But 1.9% is too much, which is why we need a three-year ban on rent increase".
Earlier Housing Minister Darragh O'Brien told Newstalk Breakfast permitted increases would have been lower in previous years.
"If you look at inflation over the last three years, that averages around 0.73% per annum – so just under one-quarter of 1%," he said.
"So, instead of a 4% increase that some tenants would have borne because that was the maximum – the maximum over the last three years would have been under 1%.
"Now, currently, inflation is running a bit higher than that but we are still looking at about 1.9%".
He added: "This is a measure that is used in continental Europe quite frequently.
"I have listened to a lot to the advice of academics in this area and indeed tenancy advocates and others and that is why I am bringing through these changes."
There were also heated exchanges in the Dáil earlier between Sinn Féin's Pearse Doherty and Tánaiste Leo Varadkar.
"You need to get real,' Pearse Doherty challenges Leo Varadkar on housing pic.twitter.com/IaSXuLWypP
— NewstalkFM (@NewstalkFM) July 1, 2021