Pressure is mounting on landlords to be upfront about the rents their charging. It comes as new figures show rents have hit an all time high across the country.
In the capital - people are paying €4,500 more each year than the peak of the Celtic Tiger.
The latest report from property website Daft.ie, shows average monthly rental costs now top €1,200 a month.
It's a 10% annual increase nationally - and well above the 4% hike allowed in so-called rent pressure zones.
Housing agency Threshold wants an independent registry to keep track of rental prices for individual properties.
CEO, John Mark McCafferty said: "What renters need is to clearly be able to see what the rent was for the previous tenancy. If there was a transparent rent register - potential renters would be able to see what the previous rent was."
However landlords say they're operating in a hostile climate - and the government's response is making the situation worse.
Fintan Mc Namara, Director of the Residential Landlords Association stated: "The government were warned four years ago that introducing rent control would aggravate the situation and create black market conditions."
Author of the report Ronan Lyons says the situation is likely to continue: "Construction activity is improving - but it's simply not enough to meet demand let alone take some of the back log from the last five years."