First-time buyers earning more than €80,000 accounted for more than a third of all mortgage drawdowns nationwide last year.
The figure is more than double that in 2004 when high earners made up just over a tenth of drawdowns.
However, the issue was greatest in Dublin where earners on €80,000 or more accounted for over half of all mortgage drawdowns.
The Banking and Payments Federation of Ireland says the figure shows how the rising cost of housing is making it more difficult for people on low or medium incomes to afford to buy or rent.
Chief Economist at the BPFI, Dr. Ali Ugar explained: "The mismatch between current demand, as well as pent-up demand, and the supply of new homes seems to have brought average sales prices relatively close to the peak of the previous cycle in terms of sale prices.
"The same mismatch also seems to be affecting rental accommodation in pushing up private sector rents where we have significantly surpassed peak rents from the previous cycle, notwithstanding the fact that rent increases seem to be stabilising."
Meanwhile, the state-funded scheme to help those in mortgage arrears is going to be extended for another three years.
Ministers Charlie Flanagan and Regina Doherty will bring a memo to cabinet this morning proposing more than €17m be invested over the next three years in the Abhaile project.
Abhaile has provided advice to more than 12,000 households at risk of losing their home over the past three years.
It is estimated around 22,000 homes are currently in long term mortgage arrears.