The proportion of houses and apartments bought by cash buyers rose from 25% at the peak of the property boom to 60% in 2014 according to new research undertaken by Central Bank economists.

Cash buyers include any property bought without recourse to a mortgage drawn down from an Irish resident bank.

That includes international private equity funds and institutional investors such as Real Estate Investment Trusts.

The number of transactions has fallen markedly in recent years from a peak of 150,000 to a low of 21,000 in 2010. The overall number of cash transactions has not increased greatly during that period. It has remained relatively steady, however, meaning that cash buyers represent a bigger part of the market due to the lower number of total transactions.

The increase in the share of the residential property market accounted for by cash purchases has come about in part because of the dramatic fall in mortgage drawdowns since the financial crisis and because of the heightened interest shown by institutional an international investors according to the article.

In a short video accompanying the publication of the research, Central Bank economist Dermot Coates said the proportion of the market now accounted for by cash buyers was neither sustainable nor "likely to continue into the future".

He said a pick-up in construction combined with a rise in mortgage lending would see cash transactions as a proportion of the overall market return to more normal levels.