There has been a 55% rise in the number of homeless families in the country since the start of the year.
New figures, published by the Department of the Environment, also show a significant rise in the number of homeless families living in hotels.
620 families were homeless in June of this year, up from 401 in January.
There are 1,318 children in these families, up from 865 at the start of the year - a 52% rise.
The vast majority of families (531) who are homeless are in the Dublin region, with 373 of those families living in hotels in the capital - a 73% rise since the start of the year.
The number of new families presenting to homeless services each month is up almost 40% since January.
The Dublin Regional Homeless Executive has described the number of families presenting to its services as unprecedented.
It says it has spent more than €4.5 million in the first six months of the year on hotel accommodation for families.
It also said the fact that the number of families presenting as homeless is not keeping pace with the numbers leaving homeless services is a significant challenge.
Agencies working in the area say that rising rents, lack of private rented accommodation and social housing are all contributing to the crisis.
The Department of the Environment has yet to respond to the figures.
Simon Communities spokesperson Niamh Randall said the high number of families living in hotels could have a long term impact on their physical and mental health.
She said research shows that children who have been homeless are at greater risk of homelessness in the future.
Ms Randall said she knows of one homless father who told his children they were on holidays while staying in hotel accommodation, but that it was only so long he could keep up the story.
She said the homelessness and housing crisis has created a "perfect storm" and that urgent Government action was required.
She said although the €25m devoted by the Department of the Environment last year to tackle the crisis has had an impact, the demand for services keeps growing.
She said the lack of private rented accommodation and social housing needs to be tackled.