Fr Peter McVerry has said the future for the homeless and the housing sector "looks grim".
He was speaking at the launch of the annual report of the Fr Peter McVerry Trust.
According to the report, the charity helped more than 3,500 people last year, compared with 383 people six years ago.
Over 2,200 people were provided with residential placements of varying lengths and more than 1,000 accessed the homelessness prevention service.
The number of meals provided last year increased from 57,000 in 2012 to 75,000 in 2013.
Fr McVerry said it is "appalling" and "scandalous" in 2014 that people are sleeping rough in Ireland.
He said frustration is growing among homeless people who believe there is no way out of the homeless trap.
He added that the Government's pledge to eliminate rough sleeping by 2016 was now impossible.
Speaking on RTÉ's Morning Ireland, Fr McVerry said rent regulation should be introduced in the short-term to tackle the housing crisis.
Fr McVerry said the Government was looking for a low-cost solution to the problem of homelessness, however he said there was no low-cost solution.
He said the Government had to get back in to investing in social housing.
He said in the meantime Ireland is totally reliant on the private rented sector for accommodating homeless people and the market had pushed these people out of the sector.
He said in the short-term rent regulation is needed, and landlords should be prevented from increasing rents by up to 50% at a moment's notice.
Fr McVerry said in the longer-term the Government was going to massage the figures of homelessness through the new Housing Assistance Payment bill.
He said this scheme would define people housed in the private rental sector as being in social housing, so there would be a dramatic drop in the numbers of people on the social housing waiting list, by massaging the figures.
Fr McVerry said official figures were showing that there were six new people becoming homeless every day in the Dublin region alone.
He said the frustration level of homeless people was also going up rapidly.
He said homeless people were now stuck in homelessness.
Responding to his comments, Minister for Social Protection Joan Burton said introducing rent caps alone will not solve the housing problem.
Ms Burton said her colleague, Minister of State Jan O'Sullivan, was examining the issue of rent caps and said that was a good idea, but she said more social housing was needed.
She said what the Government has to do is to begin an investment programme to get more houses built.