Update - 12.29pm: The brother of a man found dead in a Dublin emergency department wants to know why he was left there so long.
40-year-old Brian Hamilton was found in a chair in the waiting room of Tallaght Hospital on Saturday.
A statement from the hospital says he had been sheltering there and had not sought medical attention.
His brother Michael has told 98FM's Dublin Talks he had registered as homeless to avail of a detox programme.
Michael said: "He was in rehab, we weren't even aware he'd left, he was in residential care for his alcohol addiction and the only way we could get him into it was to register him as homeless.
"I went up to identify his body at 3:45 on Saturday and I could tell myself, and I'm not a doctor, that he was dead a long time."
It is believed Brian Hamilton had been slumped over in his chair for more than four hours.
Michael told 98FM's Dublin Talks he cannot understand how no one in the waiting room noticed he needed help.
He said: "After we identified him, I walked into the part where they sit down and said 'surely to God it's not that big a place'.
"It's quite small, I'd say about 60 foot square. How did nobody see your man slumped over for four to five hours?"
6.53am: Minister 'needs to review all homeless services' after homeless man's death in Tallaght hospital
The Minister for Housing Eoghan Murphy has been asked to order a review after a homeless man was found dead in a chair at Tallaght Hospital.
It is believed the man in his 40s had been taking shelter in the hospital's emergency department and had not sought treatment.
An investigation was launched after he was discovered unresponsive on Saturday afternoon.
Anthony Flynn from Inner City Helping Homeless says homelessness and health are beyond crisis levels.
Sadly another homeless person has passed away last night. The individual presented to a city hospital and was found dead a number of hours later in the waiting area of A&E. This is yet another indictment on the failure to implement a proper function homeless service. #Homeless— Anthony Flynn (@AnthonyICHH) April 15, 2018
Mr Flynn said: "What the Minister needs to do is to put a full review in place on all homeless services, nobody should be entering A&E to seek shelter.
"Across the country there are problems, in several hospitals you'd see people seeking shelter at night time, because of lack of beds and lack of facilities and wraparound services that need to be put in place.
"We've got a number of deaths on the streets, we've had a death in an A&E department so the Minister needs to respond."
- Digital Desk