Almost 7,000 people will spend Christmas in emergency accommodation around the country, according to the Simon Community.
The charity said such a level of homelessness is "not acceptable for any man, woman or child in Ireland in 2017".
There was a 26 per cent increase in demand for the Simon Community’s services this year, according to its annual report which was published on Wednesday.
Some 8,500 people used its services in 2016 with Simon Communities supporting almost 2,000 people to access housing.
The homeless charity operates eight regionally based independent Simon Communities.
Of those it helped, 4,134 accessed prevention, early intervention and advice services and 1,030 people accessed emergency accommodation.
Spokeswoman Niamh Randall said people in homelessness find it "almost impossible to function, to participate in society and to get involved in your community".
Shifts in policy
She acknowledged that 2016 saw significant shifts in policy with the launch of the Government's Rebuilding Ireland: An Action Plan for Housing and Homelessness.
She said that there has been progress in 2016, and Rebuilding Ireland was the "most comprehensive housing plan ever in the State".
However, she said that change was slow in coming.
“Rapid implementation is required to keep pace with demand and to keep people in their homes thus stemming the flow of people into homelessness,” she said.
“For the first time we have an acknowledgment that changes one part of the housing market, may have a knock-on effect in terms of the other parts.
“For too long we have dealt with housing and homelessness as being two separate things not seeing that housing is a key solution to homelessness.”
Minister for Housing Simon Coveney said the answer to the homelessness crisis is more homes and he said the Government is "deeply committed" to the strategy of "housing first".
He said the Government is on course to end the practice of housing families in B&Bs and hotels by the middle of next year.
He said the first family support hub opened this week – run by Respond in Drumcondra, Dublin – is part of the overall solution.
“Ultimately we need to get families into homes. We need to dramatically ramp up the number of social houses we are delivering,” he said.
