The whole of the country should be designated a rent pressure zone according to the Institute of Professional Auctioneers and Valuers.
There are 16 electoral areas across seven counties where landlords cannot increase rent by more than 4%.
The Institute of Professional Auctioneers and Valuers has said the current system contains a number of anomalies.
Landlords with new rentals or properties that have not been let for more than two years do not have to adhere to the 4% cap.
CEO of IPAV, Pat Davitt, said this is causing other landlords to ignore the rules.
Mr Davitt said: "So what we're saying to the Minister is basically what he should do is, if he wants to do rent pressure zones that are to keep the rent down, then the whole country should be put into the rent pressure zone.
"And they should be put into the rent pressure zone at market rent because, at the moment, the rent pressure zones don't take into account market rent, which is another anomaly."