The number of homeless families in Dublin has jumped by 106% in the last 12 months, according to the latest figures from the Dublin Simon Community.
The agency, which launches its annual review today, is one of several homeless groups planning to demonstrate outside the Dáil this evening.
The number of children in emergency accommodation in the city has increased by 99%, while the figures for rough sleepers are already at the levels they were at last Christmas.
Sam McGuinness of Dublin Simon said that the Government must accept that it is facing a humanitarian crisis.
"It's a total outrage when you see those numbers," he said.
"The fact of the matter is, the numbers over the last year have continued to climb, and the best actions towards doing something about them haven't been good enough.
"Any opportunity for new accommodation has been absorbed, and there's still huge percentage increases of people in emergency accommodation.
"How bad does this have to get? I mean, this is critical. We must be doing more than we're doing now."
He said that rents in greater Dublin must be stabilised and rents supplements increased, with immediate effect.
"The critical, immediate response is increase the rent supplement - people are losing their homes now because of rent increases, that's very clear," he said.
"There's a huge housing shortage and people can't compete in the rental market.
"There's also a need for somehow to stabilise rents in the city and the greater Dublin area."