Ms Quilty said access to GPs is critical as a "first port of call".

"It's one way of being able to manage your own health, putting in place preventative measures and as a gateway to other systems including the National Disability Insurance Scheme, mental health services and specialist services," she said.

"If you've got chronic health conditions and you're not able to access a GP in a timely way, it's going to exacerbate underlying conditions."

Ms Quilty said the growth of telehealth services and other innovative ways of delivering healthcare during the COVID-19 pandemic could be one way of improving access.

Outcomes are significantly worse for regional areas, with more than 7 per cent of people delaying or avoiding GP visits in Tamworth, Moree and Queanbeyan.

The data also shows single-parent families, people living alone and those in unemployment are far more likely to delay visits because of cost.

Nearly 13 per cent of unemployed people living in Maroubra and about 12 per cent of those living in Woollahra, Dee Why, Manly, Freshwater and Coogee are estimated to have put off a visit to the GP.

About 10 per cent of people living alone in Dee Why and Maroubra also delayed or avoided a visit.

Lesley Russell, an adjunct associate professor at the University of Sydney's Menzies Centre for Health Policy, said the pockets of poor healthcare access within wealthy parts of Sydney highlighted the importance of granular analysis and targeted solutions.

Loading

"It may seem surprising because these are generally well-to-do areas, but if you know Sydney and if you drive through Woolloomooloo, perhaps you're not so surprised," Dr Russell said.

Up to 40 per cent of people in some parts of the state have also delayed or avoided seeing a dentist in the 12-month period due to cost.

Nowra and other parts of the Southern Highlands and Shoalhaven rank the worst for this measure.

In Sydney, about 31 per cent of people in St Marys are estimated to have avoided or delayed a visit to the dentist, followed by 30 per cent in Colyton, Penrith, Kingswood, Windsor and Cambridge Park.

The average for Greater Sydney is 14.4 per cent of people delaying or avoiding a visit to the dentist.

Nowra also had the highest proportion of people who avoided or delayed seeing a medical specialist because of cost, with 16.5 per cent of people estimated to have done so in the 12-month period, followed by 16.3 per cent in Wollongong and 16 per cent in Port Kembla.

In Sydney, more than 13 per cent of people living in Newtown, Potts Point, Darlinghurst and Redfern avoided a medical specialist, compared to an average of 7.8 per cent of people across Greater Sydney.

"The shocking take out from this is that we talk a lot about universal healthcare but for many Australians it's not universally available and it's not universally affordable," Dr Russell said.