The Salvation Army says demand for its addiction treatment services has grown by 31% in the past two years.
About 13,000 people received treatment in the year to September.
The Army says that most people who seek help, do so for alcohol addiction.
The Army says that as it extends its services, new programmes are quickly filled because of a backlog in the community of people wanting treatment.
Addictions national manager Lynette Hutson says post treatment assessment of clients now notes whether they have a job, are staying out of trouble with the law and are in stable accommodation.
She says that after a year, 80% of clients display an improvement in at least two of these indicators.