The number of people who accessed emergency accommodation rose to 14,159 last month.
That is an increase of 150 on the previous month, when homeless figures surpassed 14,000 (14,009) for the first time.
Data from the Department of Housing shows that in May 9,843 adults and 4,316 children were in emergency accommodation.
The latest figures mean that there has been a 14% rise in those who have entered emergency accommodation in the 12 months.
Since May last year the number of families in emergency accommodation has increased by 16%, while the number of homeless children has increased by 17%.
Govt refuses to change 'failing' plan - Sinn Féin
Sinn Fein's housing spokesperson Eoin Ó Broin said that despite the month on month rise in the figures, the Government has refused to make any changes to its "failing housing plan".
Deputy Ó Broin said that since the Government ended the ban on no fault evictions last year, homelessness increased by 15%.
"This Government has neither the will nor the policies to tackle the escalating homeless crisis. How could they, they are the cause of that crisis," he said in a statement.
Labour leader Ivana Bacik has demanded "action" following the latest figures, reiterating Mr Ó Broin's comments that the Government's 'Housing for All' plan had failed on all metrics due to the rise in house prices, homelessness, and evictions.
"It is evident that without substantial State intervention, the housing market has spiralled out of control", she said.
Social Democrats housing spokesperson Cian O'Callaghan described the situation as a "disaster".
He said there had been a 63% increase in homelessness since the current Government took office and that a "third Taoiseach is continuing the appalling record of his predecessors".
Call for greater investment in social housing
The Simon Communities of Ireland has described the next six months as "an important window of opportunity in the fight against homelessness".
Executive Director Wayne Stanley said Budget 2025 and the next programme for government would set the framework for success or failure.
He said the homeless crisis should not feed a sense of "fatalism".
"Making progress on homelessness, even getting to the point where homelessness is short-term and quickly solvable, is possible," he said.
Mr Stanley stressed the need for greater investment in social housing in Budget 2025, investment in health support for those in homelessness, and support to local authorities to invest in prevention services.
Longer spells homeless increase potential trauma for children
Focus Ireland has said children are enduring homelessness for extended durations, which is increasing the potential trauma.
CEO Pat Dennigan said that without proper support, homelessness can have lifelong consequences on children.
In a statement the charity said the Government had the capability to prioritise moving many families and individuals out of long-term homelessness.
While he welcomed the provision of more social housing and new builds last year Mr Dennigan said the rise of homelessness was "a grim reality".
He said families and individuals trapped in emergency accommodation for extended periods were not being allocated new social housing.
"If the most vulnerable were prioritised we could see these monthly figures reduce significantly," he said.
