The Merchants Quay Ireland drug charity is set to appeal a decision by Dublin City Council, which refused it planning permission for a medically supervised injecting facility on its city centre premises.
The planned facility has been a source of controversy since it was first mooted in February of last year.
Drug treatment experts say it will help prevent the spread of disease, the risk of accidental overdose and death.
In addition, they say it will reduce the number of syringes and drug paraphernalia being discarded in places where they are a danger to the public.
However, residents and businesses fear the centre would bring more addicts and drug dealers to the area, increase anti-social activity and crime, and have an adverse effect on business, tourism, and safety.
Supporters of the project argue that addicts and drug dealers are already in the area, and giving them a space to inject under supervision will make the streets safer for the addicts and the public.
At the moment, Merchants Quay Ireland (MQI) supplies addicts with clean and sterile equipment for them to inject with, but the clients then have to go off-site to inject.
MQI and Dublin City Council staff then have to go out in clean-up teams using specialist equipment to pick up discarded syringes and blood-stained equipment and dispose of them safely.
Critics of the plan say a supervised injection centre only facilitates drug use, and the focus and investment should instead be on rehabilitation and detoxification.
The Government has backed the planned centre and included it in its Programme for Government.
"Merchants Quay Ireland has decided to lodge an appeal with An Bord Pleanala regarding planning permission for a medically supervised injecting facility," the charity announced in a statement.
"Extensive international evidence clearly demonstrates the effectiveness of injecting facilities.
"These facilities have been repeatedly shown to support people in addiction and in treatment, as well as reduce public injecting and drug-related litter.
"Two out of every three injecting deaths in Ireland occur in Dublin city.
"These fatalities are more than statistics - they are the tragic loss of someone's brother, mother, neighbour or friend."
Spokesman Tom Sheppard added: "We have a duty as a society to protect our most marginalised and vulnerable citizens."
Health Minister Simon Harris said he is pleased to see that Merchants Quay Ireland has confirmed its intention to appeal.