Some homeless people don't use emergency accommodation and hostels as they don't feel safe doing so, according to Fr Peter McVerry.
The homelessness campaigner says people will continue to "want to and need to" sleep on the street until they have their own safe space in emergency hostels.
It comes after Dublin City Council's CEO yesterday told The Hard Shoulder that tents shouldn't be allowed on the city streets.
Owen Keegan said there are plenty of beds available, while tents "creates a perception" that the city is unsafe.
Responding to the comments, Fr McVerry told Newstalk Breakfast it's more complicated than Mr Keegan suggests.
He said: “What Owen says is correct in one sense - there are beds available every night for people who want them. But it’s a simplistic argument.
“We have to ask why do some people not go into those homeless shelters? And the basic reason is they feel safer sleeping on the street or in tents."
He said there is some excellent quality emergency accommodation, with single rooms or two-to-a-room accommodation.
However, many other hostels are "unfit for purpose" - often with multiple people sharing a room.
Fr McVerry observed: “The biggest complaint I get from homeless people is they wake up in the morning… the people they’re sharing the room with are gone, and so are all their belongings.
"The second biggest complaint is that they wake up in the middle of the night and people in the room are injecting heroin or smoking crack cocaine in front of them."
He said such environments can create "superspreader events of drug use" - impacting not just people trying to stay off drugs, but also people who start using drugs because of what they experience in the accommodation.
Safe space needed
Meanwhile, there's also "feuding" among some homeless groups - a situation that can make some individuals feel unsafe in hostels.
Some homeless people also own a dog and are unable to take up a bed in emergency accommodation without giving up their canine companion.
Fr McVerry said the solution is to make sure people feel safe when they take a bed in a hostel or shelter.
He said: "That means providing for homeless people a single room or at least a partitioned space, where they can go in at night, lock the door, know they’re not going to be assaulted during the night, and know their belongings are still going to be there in the morning.
"If there’s somebody in the next partitioned room who wants to use drugs, it doesn’t affect them.
“Until we can provide homeless people with their own safe space in emergency hostels, some people will continue to want to and need to sleep on the street.”
He stressed that homelessness is an "appalling" way of living that's "depressing, demoralising and boring", and nobody will ever "volunteer" to go in and live in an emergency hostel.