There are calls for more subsidised housing for Sydney's essential workers after a report found the city was losing workers because of the housing affordability crisis.

The Key Worker Housing Affordability study by the University of Sydney found Australia's largest city had lost close to 20 per cent of its key workers — including emergency workers, teachers and nurses — between 2006 and 2016.

The study found it took an average 13 years for a key worker to save for a home deposit in inner Sydney.

The closest centre considered affordable for an entry-level nurse was Cessnock, more than 150 kilometres from Sydney in the Hunter region.

The areas with the biggest influx of essential workers due to the mass exodus were the Hunter Valley, Illawarra and Southern Highlands.

Police Bank, which co-commissioned the research, said young nurses were travelling from Cessnock to Sydney's Royal North Shore Hospital, and many police officers commuted to Parramatta from Wollongong.

Commuting takes its toll on workers

Police Bank chief executive Tony Taylor said the long commute was taking on a toll on workers' personal lives.

"That's got some real implications in terms of family stress and pressures outside the significant pressures of being a policeman," Mr Taylor said.

"These are the people who educate us, keep us healthy and protect us, so having them 100 per cent in the activity at the start of the shift is important.

"It plays out more to us in the trip home, because clearly after a long day, another hour and a half in the car on the way home and impact it could have on the greater family outcomes is a concern to us."

Police Association of NSW president Scott Weber said the growing commuting distances had potentially serious knock-on effects for Sydney.

"If there's a major incident on one of our highways, or lord forbid another terrorism incident in Sydney and the whole transport system shuts down, then all our key essential workers can't get to the hospitals, to the schools, and to the police stations to actually deal with that incident," Mr Weber said.

Incentives, housing subsidies to help cut commute

The NSW Government has been looking at boosting housing options for Sydney's vital workers, and one proposal put forward by groups was subsidised inner-city units.

Mr Weber said the association had been in talks with Planning Minister Anthony Roberts about the model, which was used in other global cities such as London.

NSW Police Association president Scott Weber wants housing subsidies for Sydney's key workers to be made a priority. ( ABC: Di Martin )

"We're looking at new projects that are being built in large suburbs in Sydney, and if they're building a unit of 10, 15 floors, then they're entitled to build a couple of extra floors as long as they go to key essential workers and they're at a discounted price," he said.

The St Vincent de Paul Society of NSW said Premier Gladys Berejiklian had yet to deliver on any "concrete" changes since nominating housing affordability as her top priority a year ago.

Chief executive Jack de Groot said he wanted to ensure key workers were given more housing security before next year's state election.

"The Premier came in with a commitment to do something on this area. It's one year down on her counter, one year to go to achieve something. It's time to act," Mr de Groot said.

The NSW Planning Minister has been contacted for a response.