With limited exit points in the system, a perfect storm of soaring rent prices and funding changes under the National Disability Insurance Scheme is clogging up crisis shelters such as St Vincent de Paul's Samaritan House as well as Canberra's hospital wards.

Jackson Dunkley now manages Samaritan House - the only year-round shelter for men in the ACT. But back in 2016, he was running supported accommodation in Oaks Estate for people with complex mental health needs.

When the NDIS arrived, it's funding vanished overnight as state governments largely withdrew from the sector. Instead of directly funding services, the scheme gives those who are eligible their own pool of money with which to buy them - in a bid to increase choice for people with a disability.

But while the number of disability providers has shot up in the years since, some of those original programs have been forced to close or limit services to NDIS participants alone.

That means people coming in off the street as well as those leaving Canberra's jail or its hospital wards are often being funnelled to the same remaining places.

"It's a bottleneck," Mr Dunkley said.

"Not all of those [provider changes] were related to the NDIS and the premise of the scheme is fantastic but it's all based around [gathering] evidence.

"People are saying 'I just need help now because I'm homeless and I'm hungry'."

Since 2017, the average number of nights men spend at Samaritan House, which houses 13, has climbed from below 30 to 45.

Amanda Urbanc at the Richmond Fellowship said the charity's own accommodation program was now limited to those with NDIS funding. But overall she said the scheme did appear to have increased specialist housing for people with psycho-social disabilities.

"The problem is it's so tricky to get in, especially if you're homeless," she said.

Multiple services said more people were now fronting up for support with increasingly complex needs. Many found it difficult to navigate Canberra's notoriously competitive housing and jobs market.

Others scrambled to produce identification or often costly documentation from medical experts to qualify for federal supports such as welfare or the NDIS.

The National Disability Insurance Agency, which runs the scheme, said both general and affordable housing for people with a disability remained the domain of state governments, but it was working to improve pathways into the NDIS for vulnerable people.

The Commonwealth was now investing $127 million annually into specialist disability accommodation, a spokesman said.

While the ACT government has committed millions to build more public housing and boost front line homelessness services in the next few years, some in the sector say another crisis shelter for women and those with pets would alleviate pressure in the meantime.

Housing Minister Yvette Berry said the government was wary of creating more crisis shelters without clear pathways to longer-term options as evidence suggested this could trap people in cyclic homelessness.

A government spokeswoman said the territory was focused on closing gaps between crisis and long-term accommodation which would "in turn reduce the stress and free up places in temporary and crisis accommodation".

At Safe Shelter, which opens churches and halls for men to sleep during Canberra winters, Richard Griffiths acknowledged the government's investment in the sector. But he said not enough was being done for people as they waited on beds elsewhere.

"Yes, we have a massive bottleneck in public housing, but there's no where for them to go tonight," he said.

Onelink, which acts as a hub referring people to support, got a funding boost at the last budget so it could open on weekends, but Mr Griffiths said it still wasn't a 24 hour service.

"This is a 24 hour [problem]," he said.

"Everyone has to have a referral now, this is crisis we're talking about."

At the ACT Council of Social Services, Susan Helyar agreed crisis beds were important but said Canberra's biggest problem was its lack of exit points out of shelters into affordable housing.

She welcomed the government's $100 million commitment to more public housing over the next five years but said more detail on timing and delivery was needed.

Travis Gilbert from ACT Shelter said a stay in supported housing was still much cheaper for the government than admission to Canberra's hospital or jail. He noted that as well as those with more complex needs, people were turning up to services from new demographics pushed out of the private rental market by record prices.

"We're getting more people like single parents spending 80 per cent of their income on rent as well as those in need of really specialist support, there's not so many people in the middle any more," Mr Gilbert said.

Mr Dunkley said simply building more beds was not a silver bullet for the problem, which required a housing first approach.

"If you built 100 more beds, you'd fill it," he said.

"But it's difficult...The guys we are dealing with seem to be affected almost by a perfect storm.

"Their opportunities for employment are difficult, housing is limited, and that hand up type support like [Newstart] is very limited too."

Fortunately Canberra was a generous place, he said, and its small sector worked well together to stop people falling through the cracks.

Across the sector, there are 348 accommodation places at any one time, including at women's refuges, a government spokeswoman said.

Work is also in train to develop new accommodation and case management for older women and migrant families as part of $6.5 million in extra homelessness funding set aside in last year's budget.

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