Fianna Fáil has expressed concerns about key elements of government plans to cap rent rises.
It follows a meeting between Fianna Fáil housing spokesperson Barry Cowen and Housing Minister Simon Coveney.
Under the government plan, tenants in Dublin and Cork would have rent increases capped at 4% for three years.
Fianna Fáil wants Galway, Limerick, Waterford and major towns near Dublin and Cork also included.
Barry Cowen says the 4% rate of increase is not "appropriate" - and wants the introduction of tax incentives for landlords.
Legislation bringing the measures into effect were due to be rushed through the Dáil before Christmas.
But Mr Cowen said he's open to further discussions with Minister Coveney to discuss outstanding issues.