The cost of renting in Dublin rose by almost 10% in the second quarter of this year.
That compares with a 6% jump outside the capital.
Monthly rents in Dublin are on average €110 higher than this time last year, while it's an increase of around €37 in the rest of the country.
Dublin rents are now just 3.5% lower than they were at the peak of the boom in 2007.
Director of the Private Residential Tenancies Board, Anne-Marie Caulfield, has said rents in the capital are growing faster than the rest of the country.
“The peak was as you say in fourth quarter 2007 and then nationally the rents declined by 24% so in quarter 2," said Ms Caulfield.
"Therefore, the rental levels outside of Dublin were still 18% off that peak however by comparison Dublin rents are now just 3.5% lower than they were in the fourth quarter 2007.”
Some experts put that down to the effect of Central Bank rules on home-loans, and Economist with the ESRI David Duffy has said it shows how different sides of the sector are connected.
“What we are seeing is both prices and rents going up,” Mr Duffy said.
“I think it shows the interaction between both the supply side and the rental side of the market that policies aimed at affecting one side of the market are affecting the other and that’s contributing to both rents and prices going up.”