New figures show that 468 families became homeless in Dublin last year, including 1,000 children.
This amounts to more than one family a day becoming homeless in the capital, nearly double the rate of 2013 when 240 families were affected.
90% of them were homeless for the first time.
Many are being housed in emergency accommodation such as hotels for long periods due to a critical shortage of affordable housing.
Focus Ireland says it is a serious child welfare issue and it is calling on the Government to increase rent supplement and freeze rents.
The Government has announced €3.8bn to fund more social housing but while welcome, agencies say it is a long-term solution, which does not deal with the short-term problem.
Focus Ireland is the organisation which supports families who are homeless in Dublin.
It says the problem is causing terrible damage to families and children and it is also storing up problems for the future.
Advocacy Director Mike Allen said: "It is now the case that many families and children have no additional problems when they become homeless, but when they lose their home this impacts on the children in many ways such as development, diet, education and general well-being.
"The parents are also under great stress. If this problem is not dealt with now, the damage done to these children due to the conditions they are forced to live in will deepen.
"The sad reality is that some will go on to be the next generation of early school leavers, long-term unemployed, homeless and greatly reduced life chances.
"This must be prevented as delivering housing now will help protect these children and change their futures."