The group surveyed rental properties available across the country on March 23, which was more than 69,000.
It found just one property would be affordable for a single person receiving either the Newstart or Youth Allowance welfare payments.
Only 317 of the homes — or 0.5 per cent — would be affordable for a single person receiving the disability support pension, compared to 0.72 per cent of rental housing being available for the group last year.
For a couple both living on the Newstart Allowance with two children, 777 of the homes would be affordable — or 1.1 per cent, compared to 1.63 per cent of homes being affordable in 2018.
Chambers said there was a "dire shortage of social housing", which is for people on very low incomes and could include people who have recently experienced homelessness, family violence, have a disability or simply can't get a home in the private rental market.
She called on both sides of politics to act and invest more in affordable housing for the vulnerable.
There is a shortfall of about 300,000 for such dwellings, she said.
"People on the lowest incomes are being squeezed out of the rental market," Chambers said.
"We're calling on all parties to commit to ending this shortfall — and ensure that everyone has a place to call home."
The study found only 2.2 per cent of all rental listings in the country are affordable for a single person earning the minimum wage, down from 2.9 per cent in 2018 and 2017, and from 5.3 per cent in 2016.
Chambers says this number is likely worse for those forced into insecure work.
"We know that more and more Australians are working casually," she wrote in the report.
"Around one million are underemployed. Their plight is likely to be much worse than this Snapshot shows."
Australian Council of Trade Unions secretary Sally McManus says "shelter is a basic right all people deserve", and criticised Prime Minister Scott Morrison for his lack of action on the issue.
"We need to change the rules on pay so that no person is working full time and living in poverty," she said.
"We have seen the Labor Party commit to a living wage that provides for basic living costs, while the Morrison Government has rigged the system against working people.
"We must change the government and change the rules so that working people can earn a living wage and win back the basic right to affordable housing."
The Federal Government said in March that more affordable housing will soon be available to some struggling Australians, with a federal agency offering community housing providers A$315 million ($332.7m) worth of loans at cheaper-than-average rates.
The National Housing Finance and Investment Corporation — an independent government authority established in July — raised the money through its first issue of bonds.
The corporation was set up to provide long-term, low-cost finance to support more affordable rental housing in Australia.
