Sinn Féin's published a bill calling for a three year ban on rent increases.
It would also mean a tenancy couldn't be ended if the property is sold.
The party has also called for an extension to the current emergency ban on evictions until the end of the year.
Sinn Féin's Housing Spokesman Eoin O'Broin says after consulting with constitutional experts they believe the move to ban rent increases is legally sound.
"They've made it very clear that property rights aren't absolute, they can be constrained so long as the action is fair and proportionate.
"Calling for a ban on rent increases at a time when rents have never been higher doesn't in any way negatively effect those landlords; in fact those landlords will continue to be able to get those high rates subject to the fact that their tenants are still at work and able to pay."
