The contract would provide social houses in four counties along the East Coast, including Wicklow and Dublin.
Investment company Comhar Housing will build and operate the 534 units, which will cost the state €301 million over 25 years, before they are then handed over to the relevant local authority.
The details of the contract were provided to Sinn Féin's spokesperson on Housing Eoin Ó Broin, through a Parliamentary question. He says the deal is six times more expensive than if a not for profit organisation was given the contract.