Addicts are being turned away from residential drug and alcohol rehabilitation treatment as demand pushes out wait times to six months, putting greater demand on counselling services.
Directions ACT chief executive Fiona Trevelyan said the organisation closed the waiting list for its eight-bed treatment program once it reached 10 people.
"Otherwise people sit on a waiting list for up to a year and that's not fair on them," she said.
Addicts are encouraged to access Directions community-based services while they wait, including counselling, case management, and support groups, but those too were under pressure.
"We're seeing wait lists of about three weeks for a counselling appointment," she said.
"Last week our staff on reception received 75 calls from people seeking assistance in one day."
Ms Trevelyan said Directions, like the rest of the ACT sector, was unable to afford enough staff to keep up with demand, especially for the expensive 24/7 residential treatment, as government funding continued to erode.
She said the ACT and federal government needed to invest more in the sector, but the organisation was still waiting for the outcome of the ACT budget, despite approaches to the territory government last December highlighting increased demand caused by greater use of the drug ice.
"There hasn't been a proportional increase in funding [for 10 years], what we get is CPI which doesn't keep pace with inflation and there's nothing in there for developing and improving the services at all," she said.
A spokesman for Health Minister Simon Corbell said more than $9 million of the $16.4 million spent on drug and alcohol services annually went to non-government organisations and "a range of competing priorities" in the non-government sector would be considered in the budget.
Additional federal funding for drug treatment and support services would be welcomed, he said.
The Salvation Army's Canberra Recovery Services Centre manager, Major Scott Warrington, said with more funding the charity would be able to employ staff to offer a daily outpatient service for addicts at risk of slipping back into substance abuse between detoxing in the public health system and waiting for a place in a residential rehab service.
"We are being bombarded by calls to the point where we've got a full time person working in that intake position," he said.
"We try to give them some helpful hints on how to maintain recovery until they get in."
Mr Corbell's spokesman said the waiting times for ACT Health's 10 inpatient withdrawal beds was currently less than seven days and staff liaised with other services to provide continuity of care once the person completed medical withdrawal.
Ms Trevelyan said uncertainty around federal funding meant the organisation operated on a "hand to mouth" basis making future planning difficult.
Despite the pressures Major Warrington said non-government providers were the best placed to offer rehab services, but the public sector, as the first point of call for addicts suffering from withdrawal, also needed greater funding.
At around 90 per cent, Mr Corbell's spokesman said the ACT historically had the highest proportion of NGOs providing treatment services of other jurisdictions.