More than 6,500 people will be homeless by the end of the year unless drastic action eases the crisis, one of the country's leading campaigners has warned.
Fr Peter McVerry claimed the situation has become a national emergency with the numbers sheltering in hostels and hotels expected to have doubled since the start of the year.
In a pre-budget submission to the Government the charitable trust backed plans to build modular housing to ease pressure and demand for social housing.
But it called for new laws to keep rent increases in line with inflation and a hike in the welfare supplements for people moving from homeless services into permanent accommodation.
The trust said the increase in rates should reflect how the market has changed since 2011 - up 25% nationally and 36% in Dublin alone.
Fr McVerry attacked Government plans for 150 modular units in three months and said the response to the crisis raises questions over whether ministers are committed to helping families forced out on to the streets.
"We need an acknowledgement of the scale of the problem and the realisation that this problem will continue to get worse in the months ahead," .
"The 150 modular housing units announced by Government yesterday to be delivered before Christmas will not even cover the number of new homeless families for August and September.
"With this type of inadequate response we have no option but to question whether this Government are committed to helping people in homelessness."
The McVerry Trust called for 710 euro a month to be paid out to people in need of rent supplement in Dublin with civil servants given the discretion to make higher payments if needed.
It also called for bedsits to be reintroduced.
It said they should be leased to homeless service providers to make rooms available to single, homeless people, single people exiting drug detox and people just out of prison or hospital.
The trust called for a new round of funding to prioritise projects which are shovel ready for the early part of next year and for a new emphasis to be put on developing derelict and empty properties.
It also pointed to the large number of short stay apartments available in Dublin. It said many lie unoccupied in the winter and could be leased to Dublin City Council for six months to provide safe and secure housing to the homeless rather than using B&Bs.
On law reform the trust called for a ban on the eviction of tenants when a property they are leasing is sold unless the new owner is to use it as a family home.
It said the right to a home should be enshrined in the Constitution.
Other proposed reforms include a new fast-tracked planning system for modular units in city centres, the appointment of a minister with specific responsibility to tackle homelessness and an audit of unused floor space in cities to determine options to turn empty offices and floors of buildings into apartments.
Pat Doyle, chief executive of the Peter McVerry Trust, said: " The crisis of the last few years has seen far too many people languish in emergency accommodation when they should be living in private rental accommodation or social housing. Housing, not shelter, is the answer to this emergency."