The government currently has a target of building 33,000 new homes per year under its Housing for All strategy.
O'Brien expects the bulk of Ukrainian refugees will stay in Ireland "for a sustained period of time."
"We’ve seen the devastation that has been festered upon some of the cities there," he said. "They’ll be, you know, uninhabitable for a number of years. It is more than likely that many of our Ukrainian friends that are here are going to stay for a sustained period of time. We are going to have to look at providing permanent housing solutions in that space some of the research that we’ve done and work that we’ve done in relation to planning for this, we could potentially require up to an additional 35,000 homes over the period of time should we be looking at permanently accommodating."
O'Brien said the figure of 35,000 includes both brand new homes and refurbished vacant properties.
Dublin Airport is currently being used as a processing centre for incoming Ukrainian refugees, with Citywest Convention Centre on standby if the airport becomes overwhelmed.
It's estimated that 600 Ukrainians are arriving in Ireland each day with over four million having fled the Russian invasion of their country.
Plans are being made to temporarily house refugees in tents at the Defence Forces' Gormanston camp and in Cork's Millstreet Arena.
