Safe Shelter coordinator Richard Griffiths says a "state of emergency" response - similar to those enacted in the event of a major bushfire or flood - might be needed to help accommodate Canberra's rising number of rough sleepers.
The call comes as Chief Minister Andrew Barr joined the country's Lord Mayors on Tuesday to discuss possible solutions to what's been described as a crisis of homelessness and affordable housing in capital cities across Australia.
In the past 10 weeks, Safe Shelter provided accommodation for 57 homeless men for a combined 469 nights - more than double the amount recorded in the same period in 2018.
Mr Griffiths said the speed and severity of the increase in rough sleeper numbers warranted an "urgent response".
"It's almost got to the point where we need a state of emergency response, like you would have if there was bushfire or a flood," Mr Griffiths said.
"You could open up school halls or other community halls, and put people in there."
Mr Griffiths suggested the ACT government adopt a system similar to South Australia's code red and blue response, which opens up emergency shelter during extreme weather events.
The ACT's estimated rate of homelessness fell by 8 per cent between 2011 and 2016, bucking a nationwide increase. But frontline workers, such as Mr Griffiths, are reporting a spike in demand for services, indicating the problem is far from receding.
Asked on Tuesday if the ACT government was open to supporting more homeless shelters, Housing Minister Yvette Berry said it remained "cautious" about the "development of large-scale overnight shelters which do not provide pathways to long-term accommodation".
Repeating comments made earlier this year, Ms Berry said local and international evidence had shown that accommodating rough sleepers in shelters had the potential to exacerbate trauma and "cyclic homelessness".
She said the government was instead focused on creating pathways out of homelessness, highlighting the planned renewal of 1000 public housing dwellings across Canberra in the coming years.
The government's 2019-2020 budget also included funding to build 40 units for people experiencing, or at risk of, homelessness at Dickson's Section 72. A further $6.5 million has been set aside for programs to support elderly women and migrants experiencing homelessness.
Rotary Club of Tuggeranong president Georgia Fowler, who runs a Safe Shelter in Canberra's south, said while crisis accommodation was not a long-term solution for rough sleepers, it was vital given the territory's lack of readily available and easily accessible public housing.
The rising rates of homelessness in capital cities was thrust back into the spotlight on Tuesday, as the country's Lord Mayors, along with Mr Barr, met with new federal assistant minister Luke Howarth to demand urgent action to combat shortages in affordable housing across the nation.
Mr Howarth earlier drew widespread condemnation for saying he wanted to put a "positive spin" on homelessness figures, given rough sleepers accounted for only a "very, very small percentage of the population".
More than 116,427 people were counted as homeless in the 2016 Census, up from 102, 439 in 2011.
Mr Barr said at the two-day meeting he would promote the "importance of early intervention and prevention" as the best approach to ending homelessness.
"The ACT is one of the few jurisdictions in Australia to record a decrease in homelessness at the last census," he said.
"Unfortunately, this is not the case in many Australian capital cities where homelessness is at crisis levels. There is always more that all levels of government can do and the ACT will continue to invest in strategies to improve housing affordability and reduce homelessness in the ACT."