The number of people in emergency accommodation reached 7,148 in December, according to the latest Government figures.
This figure is made up of 4,643 adults and 2,505 children.
The Department of Housing, Planning, Community & Local Government Homelessness report for last month shows that 4,643 adults were homeless in the week leading up to Christmas Day.
This compares with 4,436 adults in the last full week of November (21-27) and represents an increase of 4.8%.
A department spokesperson told RTÉ News a factor leading to last month's increase could be the additional 200 extra beds for people with no homes that were made available in Dublin from 9 December onwards.
The figures show that the number of families in homelessness remained stable at 1,205 although the number of dependents affected fell by 1.7% from 2,549 to 2,505.
The number of adults in this category rose marginally from 1,622 to 1,627.
The number of people staying in private emergency accommodation rose from 2,167 to 2,268.
This includes hotels, B&Bs and other residential facilities that are used on an emergency basis.
The number occupying supported temporary accommodation increased from 2,091 to 2,205. This includes hostels with onsite professional support.
The figures also show that Dublin continues to cater for 68%, or just over two-thirds, of Ireland's homeless population.
Sinn Féin housing spokesperson Eoin Ó Broin has called on Minister for Housing Simon Coveney to speed up the delivery of social housing to meet the growing number of people in emergency accommodation.
"For the first time since these figures were collated we now have more than 7,000 in Department of Housing-funded emergency accommodation," the TD added.
In a statement, Mr Coveney said the figures "are a stark reminder of the difficulties and the significant challenge that we continue to face in tackling homelessness."
"Since we launched Rebuilding Ireland in July last year, we've made continued efforts to deliver the plan's objectives in relation to dealing with the problem of homelessness and the Government will continue to do everything it can to tackle homelessness.
"Last year some 2,700 families/individuals exited homelessness.
"Significant additional resources for tackling homelessness are being delivered under Budget 2017 with an increase of almost 40% in the Exchequer allocation, from €70 million in 2016 to €98 million in 2017," Mr Coveney said.