Sydneysiders may be standing in their own way when it comes to creating a more affordable city, with community opposition slowing down the supply of much-needed affordable housing, experts say.

Often confused with social housing, affordable housing - which provides cheaper rental accommodation for very low to moderate income earners - receives a disproportionate share of complaints relative to other residential developments

"I'd say they get double the number of objections," said Strategic Housing Solutions principal Robert Furolo.

"People don't like development in general but they're more averse to it when it's affordable housing. It changes the tone and quantity of the complaints."

While a proposal by the City of Sydney forcing developers in the inner city to contribute to building affordable housing could help boost the much needed supply, there's still much to be done to get the community on board.

"People wrongly think they'll be living near junkies or people just out of jail, and all these fears and prejudices come up," the former mayor and state MP added. "They think the nature of the people living there will bring down the value of property in the area, bring trouble and antisocial behaviour."

University of Sydney chairman of urban and regional planning and policy, Peter Phibbs, said addressing misconceptions about affordable housing was key to overcoming the not in my backyard (NIMBY) mentality, which hindered such developments.

"Everyone is cool about it, except when it's in their street," he said. "Then you get a few ringleaders that fire everybody up."

He pointed to a proposed development by Sutherland Shire District Trade Union Club to build a childcare centre and affordable housing in Gymea, which received more than 130 objections. The development application (DA) for the affordable housing was withdrawn this week. The Trade Union Club has been contacted for comment.

While overdevelopment had been flagged as a key concern, Professor Phibbs suspects many objections would have been prompted by presence of affordable housing tenants.

Professor Phibbs conducted research into opposition to affordable housing, which looked at 401 formal submissions made against affordable housing proposals in Parramatta between 2009-2011. Forty per cent of submissions raised crime and safety as a concern and 24 per cent flagged the low income of future residents as being an issue.

Most of these fears we never realised - a later survey of residents found the majority of people had experienced no negative impacts from the developments.

Professor Phibbs said objectors to affordable housing needed to change their tune, as it was "the sort of product a lot of their kids may end up in as they've been priced out of the market".

Andrea Galloway, chief executive officer of community housing provider Evolve Housing, said Baby Boomers were the most likely generation to oppose affordable housing development - even though their own children may have to rely on it as house prices continue to soar - and noted that new-generation boarding houses in particular received a lot of complaints.

In the city of Canada Bay, where Evolve has 11 affordable housing properties, data supplied by council shows that in the 2015/16 financial year approved DAs for affordable housing boarding houses received an average of 17.6 submissions from individuals and groups within the community. By comparison there was an average of one submission for every four DAs for other development.

Ms Galloway said protracted planning and approval processes in NSW - which are only lengthened by community resistance often based off misunderstanding - were a key hurdle for increasing the supply of affordable housing.

"We had a development up in Toukley where the rumours were the people would be coming from prison using the chemist to try to get drugs as they were hooked to meth," she said.

"Then they'd hear tenants had to have proof of income, all of a sudden that changes the dynamic." "

Waverley Council mayor Sally Betts, has seen how "incredibly difficult" it can be to get the community on board with affordable housing.

In Bondi, land long-owned by The Benevolent Society was sold to Mirvac in 2013 after opposition from residents and extensive design modifications required by council and the Land and Environment Court made a proposed 128 unit development for the elderly - which would have included affordable housing - financially unviable.

In its place, Mirvac developed a recently-completed 190-unit development, where a one-bedroom apartment is currently being advertised for $750 a week.

"We had hundreds of community meetings...we negotiated and negotiated," she added. "But the development just became smaller and smaller...and it pushed [The Benevolent Society] past the break-even point."

"It was a great loss," she said, noting locals ended up with just another development that had no community benefit.