Drugs and alcohol played a part in almost 40% of homeless deaths in Dublin, a new study commissioned by the Dublin Region Homeless Executive shows.
They were found to be the leading cause of death in 38% of cases after researchers looked at 209 deaths in the Dublin region between 2011 and 2015.
The Trinity College team found overdosing was a critical factor in more than one-third of deaths.
Derek Parker from Merchant's Quay Ireland believes the homeless population is being failed:
Mr Parker said: "This report shows that the mortality rates amongst homeless people are up to 10 times higher than that of the general population.
"Drugs and alcohol are often the causes of these deaths, you see a link between homelessness and addiction.
"For us, this highlights the need to have a medically supervised injection facility up and running as soon as possible and we feel that the people who are homeless and in addiction are currently being failed.
“International evidence shows that Medically Supervised Injecting Facilities (MSIF) save lives by reducing the risk of overdose, reduce public injecting, reduce drug-related litter and increase the uptake of addiction treatment. While the MSIF is not the sole solution to Ireland’s drug epidemic, it is the first step in treating people in addiction with care and compassion, and ultimately supporting people towards recovery.”