The Peter McVerry Trust says it has worked with just under 5,000 people in the last year.
That is an 8% increase in the number of people supported by the charity 12 months ago.
313 people progressed out of homelessness and into housing last year with the support of the Peter McVerry Trust.
Demand on their services has grown by 40% since 2011.
The charity published its annual report today, which shows it opened five family hubs and seven new homeless services across eight counties last year.
It is also opening 13 new social housing units in Dublin today.
The seven two-bed units and six one-bed apartments will be filled in time for Christmas.
CEO Pat Doyle says it is thanks to public and State support.
He said: "Some of that reflects the fact that homelessness has been on the increase since 2015, 2016, 2017, and right into this year we still have the highest number of homeless people ever.
"However, we also had an opportunity to respond to them last year and we did that because, one, we secured Government contracts, and two, we secured the support of the public to help us do more and more."
- Digital Desk