"It could easily be 30, 40,000, maybe more than that, and in the context of our population that would be nearly a 1% increase in our population in a matter of a few weeks," he said of expected numbers beyond this month.
He said the government's long term aim is to provide all Ukrainian refugees with "own-door self-catering accommodation," but getting to that point would be a challenge and that there is "no point pretending otherwise."
In the short term most refugees will be housed in B&Bs and hotels.
It's expected that as many as 10 million Ukrainians will flee their country, with the Irish government planning for 2% of them to arrive in Ireland.
Gardaí are set to begin the vetting process for possible accommodation soon. Such vetting will only be required in cases where a child or vulnerable adult is placed in shared accommodation.
Minister for Foreign Affairs Simon Coveney has refused to set any limit on the number of refugees coming to Ireland.
"This isn't a question of whether we can accommodate X amount of people, it is about how we will," he said. "This is a war effort."
Minister for Social Protection Heather Humphreys has assured welfare recipients that their payments will not be affected if they choose to take Ukrainian refugees into their homes.
