A new report says Ireland will need between 40,000 to 50,000 new homes per year until mid-century.
The Irish Institutional Property report says most of these houses are needed in urban areas.
This will be due to a growing population, which is expected to reach 6.5 million by 2050.
Ronan Lyons is an economist at Trinity College Dublin and author of the report.
He told Newstalk Breakfast housing needs to be put back on the radar.
"If you look at the last 30 years, the evidence would say 'no' - over the last three decades or so we've allowed housing especially in urban areas to become increasingly scarce and increasingly expensive.
"But some of that was I think due to inattention from policy-makers.
"Housing didn't really feature on the radar, at least not in the right way, social housing was allowed to drift and there was no priority on that."
He says just in the last decade or so, the approach to housing has been wrong.
"Even in the last 15 years, the focus has been really on ensuring there aren't too many homes.
"But that's not the problem we have: we have a problem of too few homes.
"And if we want housing to be affordable and if we want people to live where and how they would wish to, we need a significant number of new homes per year".
'One year's worth of housing'
He says while using current vacant housing stock could help the situation, this will not be the solution.
"Housing is matching system, a bit like the labour market, every home is unique and every household is unique.
"And it's not the case that policymakers can say 'You don't have a home - you want to live in Cork but we have an empty property for you in Mayo, so off you go'.
"It doesn't work that way: typically housing systems either have vacant homes or homeless people.
"You've either got too many homes or too few homes - we can work, of course, to have a more efficient housing system to have fewer vacant properties but we're always going to have 3, 4, 5% of properties that are vacant.
"That's just what we see in other countries as well.
"So there's probably maybe one year's worth of housing that we could bring back into use that's currently empty.
"But we don't have a situation which I think often - at least over the last 10 years - has been in people's heads where there are lots and lots of empty homes in ghost estates: that's no longer the issue".
And he says there are also problems with the capacity of the construction sector.
"I would view viability as the single most important issue, in terms of ensuring adequate housing supply.
"And what I mean by 'viability' is when you strip out things like land costs, or strip out VAT or strip out the profit margin, how much does it cost to build a good quality in home that people in Ireland need?
"And that is very high... compared to other countries, and compared to our own incomes, it's incredibly high."
