New regulations will force landlords to ensure their properties are of a certain standard.
Minimum standards for sanitation and heating in rented accommodation are to be set down.
Shared bathrooms and landlord-controlled heating will be banned, meaning many landlords may be faced with renovation projects to bring their properties up to date.
Margaret McCormack of the Irish Property Association said some landlords will be faced with many difficulties.
She said there were difficulties with financing the required renovations and with the properties themselves, whose lay-outs or status as listed buildings may not allow renovations to take place.