Rents in Dublin continue to rise, while those in the rest of the country stagnant, or falling.
The latest results from the Private Residential Tenancies Board and the ESRI's Rent Index show that Dublin rents grew by 7.6% over the year, with some apartments showing higher than 10% growth.
That rate of increase could spell an increase of almost €100 a month for some apartment dwellers.
In many areas outside Dublin, rents are slightly down, except in Cork and Galway, which saw modest increases.
Director of the PRTB, Annemarie Caulfield said there was a higher demand for apartments than houses.
"The demand for apartments in Dublin and in the rest of the country is higher for aparatments than for houses," she said. "In Dublin, (there was) a 10.5% increase over the past year in the cost of renting an apartment.
"At the beginning of 2013, you'd have (had monthly rents of) €968, whereas at the end of the year, that same aparment would have cost you €1,070."
In addition, the difficulty first time buyers have in accessing mortgages and the lack of a supply in the housing market are driving up rental costs in Dublin, according to the index.