Property purchases by cuckoo funds and local authorities have surged, squeezing out first-time buyers.
Latest figures show a fall of 6pc in the number of new homes bought by households in the year so far.
But over the same period, non-household purchases have shot up by 60pc.
Non-household purchasers are made up of cuckoo funds, so called because these investors edge out families from the housing market.
The category also includes local authorities buying homes as social housing, and approved housing bodies.
Figures from the Central Statistics Office show that so far this year, households have bought a total of 4,434 new homes while non-householders have purchased 1,991.
This means that one in every six of all home types in the market is now being bought by cuckoo funds and local authorities.
Goodbody Stockbrokers economist Dermot O'Leary said non-household buyers have hugely increased their presence in the market.
"Household purchases of new homes are down by 6pc in the year to date while non-household purchases of new homes are up 60pc in the year to date," he said.
"The non-household sector includes entities like institutions but also approved housing bodies."
Cuckoo funds have been heavily criticised. They tend to buy blocks of houses and apartments and are seen as elbowing in, and pushing first-time buyers out of the market.
It comes as prices in Dublin have fallen for the first time in seven years.
Prices were up in the rest of the country - but they fell in the capital by 0.2pc in the year to July.
It was the first time since the end of 2012 that prices had fallen in Dublin.
Dún Laoghaire-Rathdown saw a far higher decline than the average for the capital with a drop of 6.3pc in the year.
Nationally, residential property prices increased by 2.3pc in the year, the Central Statistics Office said.
This compares with the fact that a year ago prices were rising at a rate of 10pc annually.
Prices outside Dublin rose by almost 5pc in the year.
Earlier this week banks said affordability was becoming a huge issue for borrowers.
The Banking and Payments Federation warned that people on low and middle incomes were being squeezed out of the housing market.
House prices have risen so much that large numbers of buyers now need an income of more than €80,000 to get approved for a mortgage.
Meanwhile, there has been a strong rise in house repossessions, but it is coming off a low base.
The Central Bank said 221 properties were taken into possession by lenders in the April-to-June period.
This is up from 127 properties in the previous quarter, a rise of almost 75pc.
But Housing Minister Eoghan Murphy yesterday insisted he will be able to argue that the housing crisis has been solved by the time of an election in May 2020.
"Importantly in areas... like in Dublin, where house prices have been out of reach of many people, we are starting to see them fall, which will help with affordability but we won't stop there as a Government. That's why we have a very ambitious programme for affordable homes," he said.