At least another 100,000 affordable homes must be made available over the next two decades or people on modest incomes will be at risk of homelessness, a community housing forum in Sydney has been told.

Key points: Push for more below-market rental housing to be made available

Push for more below-market rental housing to be made available NSW Government urged to introduce "inclusionary zoning" to ensure part of new development are affordable housing

NSW Government urged to introduce "inclusionary zoning" to ensure part of new development are affordable housing Important for essential workers such as nurses, teachers to enabled them to live close to their workplaces

Addressing the NSW Federation of Housing Associations conference, Committee for Sydney spokesman Eamon Waterford called for more below-market rental housing to be made available to people on lower end incomes.

"So that might be people in the bottom 40 per cent of incomes, rented at a rate that means they're still able to hold down a fulltime job but they're not really crushed by the rental cost," he said.

Mr Waterford urged the NSW Government to introduce "inclusionary zoning" which ensures a percentage of each new development is offered as affordable housing.

It has been adopted for some projects but Australia does not have inclusionary zoning across the board, in contrast to other countries.

"One in every three houses built in the UK has to be an affordable home - places like New York, Paris, LA, they all have inclusionary zoning targets set," Mr Waterford said.

He told the conference the NSW Government should move immediately to make inclusionary zoning apply to all land that it sells for development.

"The reality is they need to be looking at putting social and affordable housing on all government blocks of land, not just the ones that have public housing on them," he said.

He added that it was particularly important for essential workers such as nurses, teachers and police because it enabled them to live close to their workplaces.

Improving supply not a 'silver bullet'

Mr Waterford also warned improving supply alone would not provide a "silver bullet" that solved the crisis.

He said housing supply and demand was a more complex issue.

"The reality is we have very low interest rates, a booming economy and that means there's lots of people with cheap money available who'd like to buy into the housing market," he said.

"That means it's unlikely that even if we build another 100,000 homes a year we're going to see significant (improvements in) affordability, because the latent demand for those homes is so high."

CEO of Homelessness NSW Katherine McKernan said meeting the target of 100,000 new affordable homes would have a significant impact on people with nowhere to live currently.

"We would see a real shift in the way services are provided to people at risk of homelessness and a reduction in homelessness in NSW," she said.

"Governments can do a whole range of things to assist - from policies around inclusionary zoning, to looking at options to make the private rental market affordable, to building more social housing stock."