There's a warning the lack of supply in the rental market means people can't leave emergency accomodation.
The Simon Communities are publishing a report this morning showing just 534 properties were available to rent during their "snapshot study".
That's a drop of more than 50% from May 2015.
The study also found only 7% of places across 11 areas were available within the limits of the rent supplement or housing assistance payments (HAP) schemes.
Niamh Randall from the Simon Communities says that as well as building more, there are a few things the government needs to do to improve the situation.
She observed: "Rent certainty and enhancing security of tenure [are needed] to ensure we have got a stable, viable rental sector.
"We need to look at loopholes which allows evictions for reasons of sale or renovations - and we'd like those to be closed down so people have greater security of tenure."
She added that the limits on housing supports need to be increased "so people can compete out there".
Latest government figures showed there were 9,104 people in emergency accommodation in January.
