The number of people defined as homeless on the social housing waiting list has increased by 270%, according to the Simon Communities.
The Simon Communities are today marking the 10th Anniversary of Simon Week with a crisis forum.
National and international experts have been invited to debate the unprecedented rise in homelessness and housing instability over the past decade.
National spokesperson Niamh Randall said there are far too many people being left behind.
We really lament that things are so bad," she said.
"We never thought that ten years on we would be in such a situation where the number of people on the social housing waiting list has increased by 62%.
"Those defined as homeless on that list have increased by 270%, the social housing budget has decreased by 59% and social housing bills are actually down 79%.
"Quite shocking statistics really, ten years on," she added.