Just under 15,000 people were in emergency accommodation last month, according to the latest figures from the Department of Housing.
The Monthly Homeless Report for last month shows that 14,864 individuals accessed emergency accommodation.
This is a decrease of 335 - or 2.2% - on the November figure.
Some 10,354 of them are adults, 5,513 of whom (53%) are aged between 24 and 44.
There are 4,510 children in emergency accommodation.
The figures show that, in the 12 months to December, there was an increase of 1,546 people (12%) in the number of people recorded as homeless.
The department has also published the Homeless Quarterly Progress Report for 2024.
It shows that a total of 8,893 adults were prevented from entering or assisted in exiting homelessness during the year.
This figure represents a 29.9% increase on the 6,848 adult preventions and exits achieved in 2023.
'Temporary dip' in December figures not surprising - Simon
The Simon Communities of Ireland said the statistics "do not fully reflect the scale of the homelessness crisis".
In a statement, its Executive Director, Ber Grogan, said: "It is common to see a temporary dip in numbers in December.
"Many people experiencing homelessness find short-term respite with family or friends over the Christmas period, but this does not change their long-term reality.
"The crisis remains severe, and unfortunately we expect to see the numbers rise again in the coming months."
Ms Grogan said that, with a new Government in place, it is "time for decisive action" to address the issue.
Focus Ireland said "the figures need to be seen against a stark 12% increase in overall homelessness over the last year, with a 14% increase in children who are homeless".
Chief Executive Pat Dennigan said Minister for Housing James Browne "must work to turn this one-off decline into a new momentum".
The first step must be to deliver on the Programme for Government's commitment to ensuring that "long-term homeless families benefit from the increased supply of social housing," Mr Dennigan added.
Meanwhile the Salvation Army has described the homeless statistics as a "deafening wake-up call" for Government.
The charity said that it is witnessing a spike in homelessness across every age group.
