A 55-year-old man who had been sleeping rough was "stone dead" for more than an hour in a western Sydney city precinct before anybody noticed.
A social worker has told a NSW parliamentary inquiry there was a percentage of people sleeping rough who didn't want to be found.
"The hiddens are very hard to evaluate, unfortunately," Parramatta Mission's Meals Plus Manager Paul Moussa said on Tuesday.
"We had one 55-year-old who was lying in the centre of Parramatta for an hour and a half, stone dead, before anyone picked him up.
"The risk of homelessness is becoming more prevalent now as well, so those numbers are going to increase."
Mr Moussa was giving evidence at the upper house inquiry into homelessness amongst older people aged over 55 in NSW, with the second day of hearings held in Parramatta.
Hidden homelessness is more of an issue in western Sydney than in the city centre, Associate Professor in Urban Geography from Western Sydney University Emma Power told the inquiry.
Data from the most recent 2016 Census showed the Cumberland local government area, taking in suburbs including Fairfield, Merrylands and Guildford, had the second-highest rate of homelessness in the state.
"That was mostly people living in severely overcrowded dwellings. So that is certainly unique," Dr Power said.
She said homelessness in the City of Sydney was more likely to present visibly as people slept rough.
"We're only starting to see the tip of the iceberg of these sorts of issues in western Sydney," she said.
"That is because historically, housing in western Sydney has been more affordable."
The acceleration of housing costs in outer Sydney suburbs including western Sydney and the Blue Mountains would likely lead to growing rates of declared homelessness, or more overcrowded homes, Dr Power said.
She said many older women were increasingly facing homelessness due to having little superannuation, which they were at risk of quickly spending on private rentals.
Low levels of superannuation in older women was caused by a number of circumstances, including taking time off to have children, and later re-entering the workforce at lower pay.
"Women, as we know, also face a gender pay gap in Australia," Dr Power said.
Women who found themselves facing homelessness in older age were often determined to maintain their independence despite being unable to afford it.
"They will use the meagre amounts of superannuation they have managed to save across their life course to pay their rent out, until they have absolutely nothing left," Dr Power said.
Head of Community Housing Operations at the Women's Housing Company Christina Hough told the inquiry there were many hurdles faced by older people trying to secure social housing.
Most people understood the need for providing a baseline of identification, but older people were also required to create new documents including "home seeker diaries".
"It's the onerous process where you have to jump through hoops," Ms Hough said.
"It's just the unbelievable amount of steps and the evidence when it's very clear that someone isn't going to be able to resolve their own housing need."
The most recently-available Census data shows there are some 37,000 homeless people in NSW and more than 100,000 in Australia.
Caitlin McDowell from the Community Housing Industry Association on Monday said research showed NSW needed 317,600 new properties to meet demand to 2036 for social and affordable homes.
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