Rents in Kilkenny City can only go up by 4% a year from now on.
The city has been included in the new list of Rent Pressure Zones with immediate effect. Carlow town is not on the list but the Graiguecullen part of Laois has been included along with Portlaoise.
Ferrybank is not included either but Waterford City East and South are.
New legislation also gives the Residential Tenancies Board more power to investigate breaches and to impose sanctions.
RTB Director Rosalind Carroll says it will be much harder now to get an exemption from the 4% increase.