Campaigner Emma Metcalfe said the situation in County Armagh and the surrounding areas had created “a postcode lottery” because people have to rely on capacity at other trusts or fund their own placements.
Metcalfe, who described her own recovery from addiction as a “living hell”, set up a support service called Hand of Hope in May.
She said she had taken hundreds of calls from families at “breaking point”.
It is run by volunteers and provides peer support, hosting events for those struggling with addiction or offering advice to their families. She stressed it was not a substitute for NHS-run facilities.
“We won’t give up until there’s somewhere in Armagh for people to turn to and get well,” she said.
“Many people, especially young ones, are lost without a clear route to help. You see the awareness, but the one thing that isn’t there is somewhere people can walk in and say they need help.”
Metcalfe said there was “an ongoing crisis in the Armagh area” and called on public officials to finally fill the gap in services.
The Southern Trust said they recognised addiction was a “significant issue across our communities” and they would continue to develop community-based services “to ensure timely assessment, harm reduction and psychological support”.
“We remain committed to working with partners to improve access and capacity across the system,” they added.