Focus Ireland has said the homeless crisis is getting worse with newborn babies among those living in emergency accommodation.
The charity's annual report shows it helped a record 15,500 people last year.
That is an increase of 7% on 2017, and 14% on 2016, and includes around 1,600 families.
The annual report from the charity shows they helped 500 families out of homelessness in the last 12 months.
Brian Somers, who was once homeless but now helps others to get housing, said it can be hard for people with addictions to turn things around.
Mr Somers said: "It's not nice when you've actually come to sort of accept it, that this is the way it is going to be.
"You only have one or two other choices, you either get caught up in the criminality, the drug use, or you are going to try and get clean.
"And it's not easy trying to stay clean, trying to stabilise on your methadone when you have somebody smoking gear in the room."
Focus Ireland CEO Pat Dennigan said addressing the shortage of rental properties is key to fixing the issue.
Mr Dennigan said: "The problem fundamentally is the collapse of the private rental sector and as that continues, as a result, it is having an impact on families and households up and down the country at the moment."