The number of homeless adults and children is at a "record high" according to the housing and homeless charity Focus Ireland.
The charity, citing Government figures, said the number has risen from 7,148 in December 2016 to 7,167 last month, with 2,407 of those children.
Focus Ireland also said the number of homeless people has risen by a quarter since this time last year, when it stood at 5,715.
It said there was a slight reduction in the number of homeless families around Ireland last month.
However, the charity said that the total number of homeless families is up by one third on this time last year, from 884 to 1,172.
Focus Ireland also said that 87 families with 151 children became homeless last month.
Mike Allen, Director of Advocacy at Focus Ireland said: "This means that shockingly a child became homeless every five hours in Dublin during the month of January."
The charity has renewed its call on the Government to tackle the ongoing crisis, and called on Minister for Housing Simon Coveney to set out a "clear set of actions and objectives which is going to take over the next three years to prevent family homelessness, and provide support and new homes to those who are already experiencing it."
Mr Allen said: "In recent years we have seen a pattern of a fall in the number of families becoming homeless in December followed by sudden increase in January. This year there is a different pattern with no real fall in December, and a small fall in January.
"Behind this pattern we see continued high numbers entering homelessness in Dublin and even higher."
The Peter McVerry Trust and the Simon Communities have also criticised the increase.
Francis Doherty, Head of Communications at the Peter McVerry Trust, said the "monthly increase is significantly larger than any increase recorded during 2016 and points to the huge difficulty many single people are facing when they try keep up payments on their existing homes or to secure affordable accommodation".
Meanwhile, Niamh Randall of the Simon Communities called on the Government to urgently implement their action plan for housing and homelessness.