The average price of a home in the State is now nearly six times the average income, according to Davy economist Conall Mac Coille.
He said that this figure was roughly in line with the situation in the UK, although it was below the “boom-time” peak of eight to nine times the average Irish income.
The price-to-income ratio in the State’s housing market had fallen significantly after the 2008 economic crash, with average house prices trading at about four times average earnings in 2012.
However, the ratio, which is commonly used to gauge affordability in the market, has risen steadily since then, alongside a recovery in property values.
Mr Mac Coille’s ratio was calculated from an average asking price of €212,000 and an average earnings figure of €36,900.
The news comes as two reports, from property websites MyHome.ie and Daft.ie, showed a sharp pick-up in house prices during the first three months of the year.
"We're not in bubble territory yet, but when you see first-time buyers borrowing 15 per cent more than they were 12 months ago, I think that's a number that might concern the Central Bank, " Mr Mac Coille said.
“It’s the people at the top of the food chain, the people with higher incomes, who are buying houses because they can afford to.
“The people who don’t have those incomes are shut out.”
He cited recent Central Bank data which put the average income of first-time buyers in the State at €66,000 and that of second-time buyers at €105,000, reflecting loan-to-income ratios of 2.9 and 2.4 respectively.
“If you want the housing market to open up to larger swathes of the population then affordability becomes an issue,” he said.
The current price-to-income ratio reflected an “illiquid market”, Mr Mac Coille said, noting that only 24,000 mortgages were taken out last year, equating to just 1.4 per cent of the housing stock.
However, he said it would take a few years of double-digit price growth before the ratio returned to boom-time levels.
The MyHome.ie and Daft.ie price surveys suggest annual property price inflation is now running at nine per cent nationally and at 10.2 per cent in Dublin.
Marian Finnegan, chief economist with estate agents Sherry FitzGerald, said recent commentary about double-digit price inflation failed to take into account that average prices nationally and in Dublin were still 40 per cent below their average values in 2006.
“This piece of data is rarely shared in much of the discussion on price performance - how much prices expand this year needs to be put into context of where we are in the cycle,” she said.
Ms Finnegan also claimed that criticism of the Government's help-to-buy scheme was unjustified.
"Because we were building properties for the trade-up market, the average value of new homes sold in Ireland and Dublin has been increasing by double digits every year for the past two years - yet most commentators ignored this until this year, when they can blame it on the help-to-buy scheme," she said.
Reacting to the figures, Minister for Housing Simon Coveney said the housing market was not in the middle of another boom-and-bust cycle, but added that there was a lot of "pent-up demand" in the market.