More than 130 families, including hundreds of children, became homeless last month, figures show.
Charities working with those seeking emergency accommodation have described the record jump in homelessness – almost 150% – as shocking.
Focus Ireland, which works with the homeless in Dublin, said the figures show the economic recovery has not reached large swathes of the population.
Mike Allen, director of advocacy at the charity, blamed the prolonged crisis in private house rentals for the “massive rise” in family homelessness.
“The repossession of buy-to-let landlords, often by banks owned by the Irish people, is a growing phenomenon and may account for up to half the recent cases of family homelessness,” he said.
“There are over 35,000 buy-to-let landlords who are more than a year in arrears on their mortgages and we have been warning government about this impending problem for over three years.”
The charity said there are 269 children included in the 134 families who became homeless in January, compared with 54 families in the same month last year.
Focus Ireland said the highest monthly increase on record was “a timely reminder to voters and the political parties that the recovery has not reached a large number of communities and people”.