Focus Ireland has called on the Government to set aside €500 million in Budget 2015 to help deliver more than 3,000 homes.
The charity made the call in its pre-budget submission as it published new figures that show 45 families became homeless in Dublin in September. Focus Ireland said 350 families had become homeless so far this year in Dublin.
It called for the Government to raise rent supplement rates on budget day to stop the rise in the number of families losing their homes.
The charity said changes to petrol prices or VAT are usually made with immediate effect on budget day so a move to keep families in their homes could be done in a similar way.
Its director of advocacy, Mike Allen, warned that the homeless crisis for families is "continuing unabated". Mr Allen said it was critical that the Government did not just provide for emergency accommodation but also built more social housing.