The number of men, women and children experiencing homelessness increased in May compared to the previous month.
Latest figures from the Department of Housing show 15,747 adults and children were accessing emergency accommodation.
The figure is up from 15,580 in April.
The number of children is 4,844 - up from 4,775, while the number of adults increased to 10,903 from 10,805.
Focus Ireland CEO Pat Dennigan said the figures show "the Government's current approach to homelessness is failing".
"There needs to be far more urgency in the Government's response to help end this terrible human crisis," he added.
The charity's CEO called on the Government to reform the Housing Assistance Payment scheme and "must deliver a radical policy shift to provide a range of housing".
'We just heard this week that the new Housing and Homelessness Plan is now delayed until at least September," Mr Dennigan said.
"We need action now and there are some actions the Government could take immediately to improve the situation," he added.
The Dublin Simon Community said that while a housing crisis may be on the political agenda, "its most devastating consequence - homelessness - remains overlooked".
It added that "there is doubt as to whether the Government cares about addressing the instability, harsh and immediate realities" of the homeless figures.
The Dublin Simon Community CEO said "stability must be at the forefront in addressing the chaotic housing market with chronic shortages".
"All eyes are now focused on a housing plan and Budget 2026 as to what it will provide as incentives to kickstart a greater housing supply in a market that has plateaued," Catherine Kenny said.
"As the new rental rules will do little to help those stuck in emergency accommodation, the next national housing plan, due in a few weeks, must bring meaningful measures for those who are experiencing homelessness," she added.
Meanwhile, Executive Director of the Simon Communities of Ireland Ber Grogan said solutions presented by the charity "time and again", have not been acted on with the urgency the crisis demands.
She has called for decisive action.
"We haven't seen a decrease in homeless figures for five months - and the last drop was due to temporary seasonal relief over Christmas. This is not progress. We don’t want to keep breaking these records. Behind every number is a person - a family, a child, a life in crisis. The time to act is now," she said.
The DePaul charity said that while the situation had been described as "a national priority requiring immediate and radical action", homeless services are not seeing evidence of this.
Chief Executive David Carroll said it was "hugely frustrating".
He called on the Government to start showing evidence of a realistic response to the crisis and to act now.
"There are no quick fixes - this is time for systemic change and radical action," he said.
The Salvation Army warned that the full impact of homelessness on children would only become clear once they reach adulthood.
As one of the biggest providers of homeless accommodation in Dublin, it said the latest statistics "paint another harrowing picture" of the housing crisis.
The Salvation Army's Homeless Services Ireland Lead Erene Williamson said the emotional, physical and developmental needs of the children must come first.
"Children within homeless families will most likely experience trauma and a host of challenges growing up without a secure home," she said.
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'Shameful milestone'
Sinn Féin and the Social Democrats said the rising homeless figures were a result of Government failures.
Sinn Féin's housing spokesperson Eoin Ó'Broin said the increase in child homelessness figures over the decade "is the direct result of the failure of Government to deliver a sufficient volume of social and affordable homes".
The Social Democrats housing spokesperson called the child homelessness figures "a shameful milestone".
Rory Hearne said the figures are a "direct result of policy choices made by the Government", adding such failures are "intolerable and inexcusable".
"The state could be facing a national redress scheme for children who have been in emergency accommodation," he said.
