Over 160 of those are in the midlands prisons.
Over 800 prisoners are on a waiting list for prison-based addiction counselling services.
Figures released by the Justice Minister show 101 of those are in the Midlands Prison, which is among the highest number in the country.
The total figure also includes 64 inmates waiting for services in Portlaoise Prison.
Dublin's Wheatfield Prison accounts for the largest number of those on a waiting list in the country, at 191.
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