Sydney and Hobart have been named the least affordable cities in Australia for renters, in the latest release of the Rental Affordability Index.
The biannual statistics analyse the price of rents relative to household incomes using census data, and provide a price index for rental housing markets.
The research, by National Shelter, Community Sector Banking and SGS* looks at eight different household types - including a single pensioner, a single person on benefits, a single full-time working parent, a dual income couple with children, and a student shared house.
Ellen Witte, from SGS Economics told the ABC that Australia is facing a housing crisis.
"Those hardest hit are the low income groups but even working families. So if we look at a single income family, working family, they would pay 30 to 71 per cent of income on rent. Now that's clearly unsustainable."
Households that have to spend around 30 per cent or more of their income on renting are classed as being under 'housing stress'.
It means it affects their ability to afford other primary needs like food, power, water and health services.
Most of those renting in Greater Sydney fall into that threshold, spending around 29 per cent of income on rent.
That was followed by 25% in Greater Brisbane, 24% in Greater Melbourne, 22% in the ACT and 21% in Greater Perth.
Ellen Witte says pensioners and young people are among the worst affected, spending more, as a percentage of their income, on rent than others.
"They may pay 59 to 97 per cent of rent so that basically means there are no rentals available for them in the current market. That's leading to overcrowding of housing, people having to stay in boarding houses, and increasing levels of homelessness. And that's what we see when we walk down the streets every day."
In Sydney, a number of suburbs within a 10 kilometre radius of the CBD have been listed as being 'severely to extremely unaffordable'.
They include Darling Harbour, Dawes Point, Haymarket, Millers Point and The Rocks.
26-year-old Millers Point resident Elaine Kerins moved into the area a few months ago, and says rental costs are worrying.
"I think it's possibly relative to the fact that it is so centrally located, near all the amenities and the main sites of Sydney, but it also means on a more personal level that I'm not saving very much for my future as a young adult. And it makes it more difficult to think about saving for the future in terms of investing in a property myself down the line and also obviously having money towards other things long-term as well."
She says that, in comparison to when she lived and worked in Ireland and the UK, the relative increase in cost has been "astounding".
"It is the most expensive city I have ever lived in so far, and I certainly do find it a massive adjustment to get used to, and to be able to budget in order to afford it."
The region of Greater Melbourne, meanwhile, has become slightly more affordable but still remains costly for renters.
Albert Park, Middle Park and Brighton East were cited as the most unaffordable for tenants.
More surprising, though, are the findings for Greater Hobart in Tasmania, where there is a shortage of housing.
There, the median gross income for those households is $52,800 a year, but around 25 per cent of that goes to rent alone.
Adrian Pisarski, from housing advocacy organisation National Shelter, says vulnerable communities will find it increasingly harder to find somewhere to rent at an affordable price.
"Unfortunately there's not many solutions on offer. We have been underinvesting in affordable and social housing for a very long time and there is virtually no room - there is no room on any public housing waiting lists in the country. There's a massive backlog of applicants, so what I think what's going to happen is people are going to be increasingly forced into share housing or into staying with their parents for longer. But even for pensioners I think we're going to be seeing more share house options come up."
