Over 9,000 people accessed emergency accommodation last month including a "depressing" number of children.
The homeless figures saw a jump of 342 on the previous month and homeless charities said the reasons were because of rising rents and private landlords leaving the market.
Last month, 6,825 adults, 2,667 children and 1,180 families availed of emergency accommodation services.
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There were a total of 9,492 people using services - a jump of 342 on the previous month.
Head of Policy and Communication at the Simon Communities of Ireland Wayne Stanley said the increase in homelessness is "deeply concerning".
He said: “We know that the homelessness crisis has been driven by structural issues of affordability and supply in our housing system. This has been exacerbated as growing price inflation heaps further pressure on stretched households.
Mr Stanley said the structural issues that are causing the housing crisis must be addressed but urged actions be taken to protect those at risk of homelessness.
He said: "The rates for the Housing Assistance Payments (HAP) should be increased to help support people out of homelessness.
"The Minister will be receiving a report from the Housing Agency on HAP rates in the coming days and his response to this needs to be swift in support of the most vulnerable in our society."
Focus Ireland CEO Pat Dennigan said the increase in homeless figures can be put down to private landlords leaving the market.
He said: “What’s clear is the number of landlords leaving the market is having a direct affect on the consistent increase in homeless figures over the past 6 months.
"It’s a reality that the most vulnerable are relying on the unpredictable private rental market where options are scarce across the country."
Mr Dennigan added that the "most depressing" thing about the new figures were the 2,667 children accessing homeless services.
He said: “All homelessness is wrong, but it hurts children the most as it causes trauma, contributes to malnutrition, and can cause long-term damage."
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