The number of people who are homeless and use drugs has almost doubled in the past six years.
The figures, released by the Health Research Board, have been described as "deeply concerning".
They show that the proportion of people being treated for problematic drug use who are homeless has jumped from 5.1% in 2010 to 9.6% in 2016.
The number of people who inject drugs also remains high at 2,960, with heroin being the most common drug reported.
Tony Geoghan from Merchants Quay Ireland believes the true number is probably higher.
"Homeless people are becoming entrenched in addiction, and those caught in addiction are being left behind."
"The Rebuilding Ireland strategy is failing people with complex needs, and I would urge Minister Murphy to address this issue so that we do not leave people in addiction behind", he said.