In London, £75 ($145) a week will get you a single room in a flat on the edge of the inner city. In New York you can pay US$180 ($225) a week for a room in a three-bedroom, two-bathroom “huge” duplex, with all bills except internet included.

In Sydney, pay $230 and you get one room above a real estate agency, with a shared small kitchen and toilet, and a shower that does not even have a curtain.

When thinking and writing about housing affordability, the focus is often on the high cost of buying, but as noted by the Guardian’s Greg Jericho, for many people housing affordability is about being able to pay the rent, and rental costs are keeping pace with rocketing house prices.

The latest national rental affordability survey by Anglicare found that, of the 65,614 rental listings nationally on the weekend of 11 and 12 April, fewer than 1% were appropriate and affordable for a single person on government support. Of the 51,000 properties in the major cities, only one, a room in a share house, was affordable for a single person on Newstart. That means there were zero affordable options for an unemployed single person in most Australian cities. Housing options started to appear only when people were willing to spend more than 30% of their income on rent.

Graham Marshall, 48, was living in a three-bedroom townhouse in Sydney paying $540 a week in 2013 (he says the same place now costs about $700 a week) when he was diagnosed with rheumatoid arthritis. He was working full time but quickly had to stop because of the physical nature of the job, and within months was unable to keep up with the rent.

Today he receives $622 a fortnight from the disability support pension (DSP) and $460 goes to his rent, a room above a real estate agency in Sydney’s west.

“There’s just no support any more. It’s become unbearable. I feel like I am trapped in a room. I’m not in jail, but I might as well be. I have no funds, the cost of rent, electricity, just to communicate with people, it eats up everything. If you’re lucky you can get some food out of what’s left,” he says.

Rental affordability is not just a Sydney problem. The national survey found that although the market in regional areas was not as oppressive as Sydney, it was still a major issue. Single people living on unemployment benefits would have access to fewer than 10 suitable properties out of the 14,000 regional properties surveyed.

Single parents on parenting payment would find 3.7% of rentals suitable, and single parents on Newstart would find only 0.6% of rentals suitable.

Marshall has lived in Sydney for 15 years, eight of which were spent working for the army as a combat engineer in the 1990s. But soon he may leave for Melbourne which, although still expensive, has more support services and accessible housing.

The rental situation has been labelled a “national emergency” by Australia’s welfare rights network, and Anglicare’s executive director, Kasey Chambers, has warned it could damage people’s health.

The rental crisis and the housing cost crisis are, of course, not mutually exclusive. A report released by the Australian Council of Social Service (Acoss) earlier in April said that while house prices had risen 92% between 2002 and 2012 and flats rose by 40%, rents for houses had increased 76% over the same period and the cost of renting a flat had gone up 92%.

It also noted lending for investment housing rose by 230% and lending for owner-occupied housing rose 165% between 2000 and 2013. A recent Wall Street Journal article comparing house prices as a proportion of income found buying property in the industrial NSW city of Wollongong was more expensive than buying in New York, and rent rises were keeping pace with house prices.

The housing boom is not only locking people out of the market, it is locking them out of the actual houses.

After low-income earners and people on social welfare, young people are the most disproportionately affected by the crisis. Youth Action’s director for policy and advocacy, Eamon Waterford, estimates most young people living in Sydney are either continuing to live with their parents until they are in their 30s, or spending 50% to 60% of their incomes on rent.

“It limits their capacity to engage in community. Previous generations said ‘back in my day, we didn’t have it so easy’, but on an economic level there is long-term significant impacts on ability to save money [because of the high rents],” he said.

“The typical trend we want to see is move out, rent, save, buy a house and they’re set. Now we’re at a point where if you’re on a median income in Sydney and renting, forget about saving for a deposit.

“It also causes a stratification between generations. Older generations are getting wealthier because they got in [to the housing market] at the beginning, but there is also a stratification between young people: those whose parents can afford to help them and those who can’t.

“The haves and have-nots are having significantly different trajectories in their lives simply because of what their parents had.”

Jess, 29, who did not want to disclose her last name, said she had been living in share houses since she moved to Sydney from South Australia four years ago. She is just about to move out on her own and says she has been saving for a house deposit since she started full-time work. She currently has $12,000.

“It’s taken years, years and years. It was going quite well when I started [in Adelaide] but ever since I moved to Sydney I just can’t seem to get anywhere near my targets, no matter how much I cut down on shopping or evenings out,” she says.

“Not only that but I find myself moving further and further away from work. The place that I used to rent came up on realestate.com a few months ago and had gone up by almost $500 a week since I lived there. I’ve just stopped thinking about it. I can barely afford to rent and that’s what I’m going to be doing for the rest of my life.”

Waterford says an often overlooked result of the rental crisis is people house-sharing for longer. Where it used to be the domain of university students and young people in their first year of full-time work, now people are house-sharing in their 30s and 40s.

As Chambers points out, the ramifications of the rental crisis ring far beyond people’s bank accounts.

“Housing and employment are inextricably linked, as are housing and health and housing and education,” she says.

“If we don’t get housing right the others will become casualties. We know there isn’t a simple fix. Housing is a complex area. It involves all departments and levels of government. We need government leadership to actually take this action beyond election cycles.

“We have to recognise that inadequate income is a severe barrier to secure housing and therefore in turn a barrier to employment, education and health.”

Welfare groups and housing advocates almost unanimously agree that one of the first areas of change should be Australia’s negative gearing policy which allows people to make heavy reductions on their taxable income by using investment properties.

However, any reforms to tax need to be coupled with policies which ensure more affordable housing is built.

“People are right about supply [being a major factor in rental unaffordability], but it’s supply and other things. It’s also about spending money on affordability. Other cities are doing this much better than Sydney. London has a requirement that any development with 10 dwellings or more, 35% has to be affordable,” Waterford says.

“It’s about practically increasing supply, putting a requirement people build sustainable, affordable things.

“Sydney should look to the cities it aspires to be: London, New York or even Paris. Cities should be for everybody, not just rich people.”