The Environment Minister Alan Kelly says landlords cannot just 'gazump' new rental prices for tenants.
The coalition plans to stop landlords from raising rents every year, and it is limiting increases to once every two years.
Fine Gael and Labour agreed the plan last night - but it still needs final approval from the Cabinet next week.
The proposal means a promise by Mr Kelly to give rent certainty by linking any rises to inflation will be abandoned.
Housing and homeless charities have welcomed the new plans, but they are warning that the legislation must be introduced in coming days.
Chief executive of Threshold, Bob Jordan, says moves must be made quickly in order to prevent widespread and immediate rent increases.
Minister Kelly told Galway Bay FM he expects the new measures to be followed by landlords.
The Finance Minister says the new laws can be rushed through to stop landlords from hiking rents on vulnerable tenants.
Michael Noonan was responding to reports that some landlords are already increasing rent, before they can be stopped by new regulations.
Minister Noonan says tenants will be protected under other laws:
The Private Residential Tenancies Board (PRTB) has this evening reminded tenants that rent can't be increased within 12 months of a tenancy beginning - or within 12 months of the last increase.
In a statement it also says it is illegal for landlords to ask for more than the 'market rent', which is the amount that a willing tenant would be wiling to pay for a similar property in a similar place.
Meanwhile, the Father Peter McVerry Trust has also welcomed the move towards rent certainty.
However, CEO Pat Doyle says the law needs to be changed quickly to avoid landlords hiking prices while they still can: "It will allow some of the other initiatives like the NAMA housing stock, social housing stock coming into play, the Minister's own capital building programme and the modular housing ... and it will calm the market down".
"The key issue for us is that they need to rush the legislation through immediately in order to ensure that there isn't a spike in the rents."
Political correspondent for The Irish Times, Fiach Kelly, outlined the deal on the table for the Cabinet on Newstalk Breakfast.
