There are some 436,000 social housing dwellings in Australia, accommodating more than 800,000 people.
But the nation's stock is not keeping pace with growth in the rest of the housing sector, a new report released on Wednesday by the Australian Institute of Health and Welfare showed.
The institute's report on housing assistance showed the proportion of social housing decreased from 4.7 per cent of all dwellings in 2010 to 4.2 per cent last year.
Social housing is defined as public housing, community housing, state-owned and managed Indigenous housing, and Indigenous community housing.
"While the number of households in social housing has generally increased over the decade to mid-2020, social housing has not kept pace with the growth in the overall number of households in Australia," the institute stated.
There were about 802,000 occupants in Australia's social housing network in 2019/20, up from 797,100 the previous year.
Across all social housing, 62 per cent of occupants were women, and 49 per cent were aged 40 years or older.
Demand for Commonwealth rental assistance climbed sharply last year as COVID-19 took a toll on the national economy.
Families receiving Commonwealth Rent Assistance rose from 1.29 million in 2019 to 1.7 million in late June last year, the institute found.
That figure had been 1.31 million in 2018 and the previous peak was 1.35 million in 2016.
The total rent assistance was $4.7 billion in 2019/20, up from $4.5 billion the previous year.
Of those people on rent assistance, 38 per cent were also on JobSeeker payments - up on the 20 per cent in 2019.
The report also showed the number of single, no children, share income units on Commonwealth rental assistance nearly doubled, from 163,300 to 321,900.
Nearly a third, or 29 per cent, of individuals or families on rent assistance were still considered to be in rental stress.
The report comes as the Victorian government announced residents are starting to move into new social and affordable housing.
More than 240 homes are available under the state government's $5.3 billion Big Housing Build, announced in last November's Victorian budget.
The program aims to construct more than 12,000 homes for social housing across the state over the next four years.
