The State investment agency is sitting on an unused land bank the size of 170 Croke Parks.

IDA Ireland has more than 2,700 acres lying vacant, which accounts for more than a quarter of its entire estate portfolio.

The publicly-owned lands include more than 220 acres in Dublin, more than 500 acres in Cork city, more than 120 acres in Galway city, 290 acres in Limerick city and 70 acres in Waterford city.

Other urban centres such as Dundalk (153 acres), Sligo (104), Kilkenny (42), and Navan (62) are also home to significant parcels of unused sites.

The IDA says they are being “actively marketed” to overseas companies potentially thinking of setting up a base in Ireland.

But Maurice Quinlivan, Sinn Féin’s jobs, enterprise and innovation spokesman, who obtained the figures, has called for a full audit of the land bank to see if some of it can be used for social and affordable housing.

“We are in the middle of a housing crisis and we need to see what sort of publicly-owned land bank we have, some of which could be handed over to local authorities, for a local authority-led build of housing across the State.”

Mr Quinlivan said foreign direct investment is very important to Ireland and it was important to have land available for companies, but he added: “I’m sure there is land owned by the IDA that can be used for social and affordable housing.”

An audit could determine where land was suitable, in terms of infrastructure and proximity to urban centres, for housing development, he added.

‘Most critical resource’ Last month, a Government advisory body urged the State to look to land it already owns to solve the housing crisis.

The National Economic and Social Council said land in public ownership is the “most critical resource” available in tackling the issue, and noted a “substantial amount” of such land is located in cities and towns.

Asked about the IDA land bank, Minister for Jobs, Enterprise and Innovation Heather Humphreys said availability of an “adequate supply of marketable serviced land” is a “key element” in the agency’s ability to attract foreign investment.

“The availability of property solutions allows projects to commence at an earlier date by diminishing much of the difficulties associated with land acquisition, planning and construction,” she said.

“It is, therefore, an important means by which the IDA can encourage and attract new investors to Ireland, particularly to the regions.”

Latest figures show potential investors made 135 visits to IDA sites during the first three months of this year.

Just over a half were in Dublin (69). Cork (10) and Galway (10) were the next most popular locations, followed by Limerick (eight), Louth (six) and then Sligo (five) and Waterford (five).