Fr Peter McVerry has said that the homelessness situation in Ireland is now “beyond a crisis”.
His comments come following reports that seven people have died sleeping rough in less than three months.
This week, a middle-aged man was found unresponsive in a tent in school grounds in Ranelagh in south Dublin - and another, believed to be from Lithuania, succumbed outside the Four Courts.
The man outside the courthouse was aged in his late 30s and reportedly may have died due to a drug overdose, Taoiseach Leo Varadkar said.
The Ranelagh victim had previously been offered shelter.
Fr McVerry warned that the crisis could deteriorate further.
“House repossessions are increasing, rents are continuing to rise at an alarming rate, and Brexit will see many employees relocating to Ireland and looking for somewhere to live,” he said.
Speaking at a symposium on housing, “Housing in Ireland: Philosophy, Policies and Results”, held in Trinity College Dublin, Fr McVerry said the number of people in emergency accommodation has doubled since January 2015.
"The numbers have increased every month since July 2016, when the Government published Rebuilding Ireland, its Action Plan on Housing. In October 2017, there were almost 2,000 more people in emergency accommodation than in July 2016, with the number of children going up by almost 850,” he said.
He said the Government is "unable or unwilling" to acknowledge that 'Rebuilding Ireland' is not working.
The homelessness campaigner called on the Taoiseach to declare housing emergency.
"He needs to bring all the relevant parties around a table, reach consensus on a new plan, and then demand that everyone works from that plan, as a priority,” Fr McVerry said.
Trinity College Economics Professor P.J. Drudy said Ireland has "tolerated a dysfunctional housing system for far too long, with unwarranted reliance on the private sector to meet an essential need.”
He said private developers built 75,400 houses in 2005, in locations where the houses were not needed.
“Last year they built only a fraction of the 30,000 to 35,000 houses it is estimated Ireland now requires. Indeed, the official figure of 14,400 new houses in 2016 is reckoned by several commentators to be an over-estimate,” Prof. Drudy said.
He claimed private property developers are now failing to provide affordable homes.
“Most [private property developers] view homes as ‘commodities’ to be bought and sold like any other commodity – simply a means of making money. Some are now hoarding land and drip-feeding small numbers of executive-type homes onto the market to maintain high prices.”
He said this has led a sharp increase in the cost of housing, with new private house and apartment prices are now well above their peak in 2007.
Prof. Drury said overall house prices in Dublin have increased by 87% in the last four years.
“Private landlords are also charging unaffordable rents. This is a housing bubble!” he said.
He said the Government must provide resources to build at least 10,000 homes annually for househoulds on the waiting list, as well as a further 10,000 'cost-rental' and self-financing homes for those ineligible for social housing.
Dr Sinéad Kelly, Department of Geography, Maynooth University, highlighted the impact on housing of the adoption of neo-liberal policies.
She noted that the neo-liberal drive towards market provision in an increasing number of areas, including housing, is accompanied by a reduction in state spending, and a withdrawal of public provision in favour of privatisation and outsourcing.
"In Ireland, the move towards treating housing as a commodity and a financial asset has been actively supported by State policies, including, for example, capital gains tax measures favourable to investors, the approach adopted by NAMA, and the treatment of real estate investment trusts (REITs),” she said.