Long waiting periods to exit emergency accommodation and access treatment is taking its toll on the mental and physical health of the homeless population, according to the Dublin Simon Community.
Its latest annual report shows wait times for mental health services increased by 68% last year, while detox services wait times grew by 13%.
The charity said a lack of options for people in all services to "move-on" was identified as a significant risk in triggering relapse.
It has said the ongoing lack of accessible one and two-bed properties across the country has led to a "grim" situation.
The report also shows that 75% of those presenting to Dublin Simon's clinical services are presenting for the first time with physical health and addiction issues and 68% of those accessing counselling are first-time presenters.
The Dublin Simon 2021 Annual Review also revealed the rapidly increasing demand for detox and counselling services among the homeless population, which is outpacing the capacity for services in the capital.
Over the last three years, waiting times for detox and counselling increased by 120% and 130% respectively.
Of 408 counselling clients last year, 20% were on the waiting list for over 60 days, as the service managed a series of increasingly complex cases.
Dublin Simon said 44% of detox clients have been homeless for over five years.
The number of people accessing its education and employability services increased by 62% in 2021.