RURAL Ireland could help solve the housing crisis, Micheál Martin has said.
Untapped potential like renting out spare rooms in homes in the country may supply extra accommodation, the Fianna Fáil leader added.
He reiterated his call on the Government to take steps to address the country's problems with housing supply.
The Cork South Central TD said: "There's a lot of housing stock out there that is not being used.
"We already have some incentives, but the evidence is the way the market is developing, with large institutions coming in, there are many people with two houses, three houses, some who because of their own personal finances are renting out apartments or whatever.
"But they're finding it difficult.
"And I think we've got to get that balance right, make sure that we have a steady flow of people into the market plus, you know there's an existing incentive for example if you have a house and you are living alone that you get an incentive to rent out a room, and so on.
"And I think there's untapped potential there, as there is in rural Ireland, in terms of utilising accommodation that's not been fully utilised."
Fianna Fáil's general election manifesto next year is expected to address the challenges facing housing.
Mr Martin said: "I think, for us, there has to be a dramatic increase in house building. And we will be saying to people, you know, there are two huge issues here, housing, we can't do it in a piecemeal basis, we can't do everything.
"But we're going to sort this housing out and Fianna Fáil historically built the biggest estates of the past in swathes of Dublin, Cork, Limerick, Galway, which dealt with housing crisis of that era."
He said the current situation could cause society to implode and acknowledged that young people faced huge challenges in affording rent or being able to buy a house.
"And too much of their income is being eaten up by excessive rents. And the rents have gone too high and they have to be controlled."
Taoiseach Leo Varadkar has rejected calls for a rent freeze and said the solution to the housing crisis is rent control and an increase in the supply of social and other housing.
Mr Martin said: "In the recent by-elections it was on every doorstep at all levels, homelessness, housing, and young people trapped, not in the position to afford housing, not in a position to afford very high rents living with their parents.
"Lots of stress and strain anxiety and despair around the whole housing issue."