Homeless children put up in a hotel are banned from playing in the garden but dogs are allowed, an Oireachtas watchdog has heard.
Fr Peter McVerry revealed a seven-year-old boy in the emergency accommodation asked his mother why animals could go into the space on a sunny day but his family could not.
"I heard the story of one family, they were living in an hotel bedroom, they are not allowed to mix with other residents, they are not allowed to eat in the restaurant," he said.
"They have to come in the back door, (they're) not allowed in the front door.
"They weren't allowed to sit in the garden. It was a lovely sunny day and all the paying residents were in this garden and the parent decided to bring the kids for a walk.
"While walking through the garden the seven-year-old boy saw a bowl on the ground with water and says to his mammy 'mammy why is the dog allowed in the garden and we're not'."
The campaigning priest detailed the impact of homelessness after telling the special Oireachtas Committee on Housing and Homelessness that Taoiseach Enda Kenny should declare a national emergency over chronic housing shortages.
"He would do if we had a foot and mouth disease in the morning," he said.
More than 6,100 men, women and children were homeless at the end of April and living in emergency accommodation such as B&Bs, hostels and two and three star hotels - an unprecedented crisis.
The trust told the committee that councils should be using compulsory purchase orders to buy vacant properties which could be turned into units for homeless families.
"I don't know what the local authorities' problem is," Fr McVerry said.
"The National Roads Authority had no difficulty compulsorily purchasing houses and land when it wanted to build motorways. There was no constitutional problem.
"Why can't we compulsorily purchase houses for the far more important issue of providing people with homes."
Fr McVerry estimated that at least 2,000 families people have been made homeless as a result of the Department of Social Protection not increasing rent supplement payments.
The trust called for another 1,500 modular units to be built in the Greater Dublin area and for the rapid builds also to be used for student accommodation to free up 5,000 housing units in the rental sector.
Fr McVerry said he expected 100,000 people or families to be on social housing waiting lists this year.