Rents in Dublin grew by 3.5% in the first quarter of the year - according to the latest index from the Private Residential Tenancies Board.
The index examines the actual rent paid for houses and apartments and shows further evidence of a two tier system.
Rents outside the capital fell by 0.3% in the same period while the growth in the Dublin market is driven mainly by demand for apartments.
Karl Deeter of Irish Mortgage Brokers said the figures are indicative of what is happening in the property market as a whole.
"If you see rental yields falling outside of Dublin then you would expect that there would be a continued decline in property prices when you use property based on the value of rent as a determinant to come to that price," he said.
"I think there is a lot more here than just having a report that tells a rental story it actually tells a story of the entire property market in many respects."