The complaints account for 18.2 per cent of those made about public hospitals in NSW, nearly double the next most complained about health district.

The Western Sydney health district received 10.4 per cent of the state's complaints about public hospitals, with a total of 176.

South Western Sydney was next with 9.3 per cent, a total of 158.

The results, collated in the Health Care Commission's annual report for 2022-23, show the Hunter New England Health district's complaints trajector trending up from claiming 12.8 per cent of complaints in 2018-19, to 14 per cent in 2019-2020, then jumping to 18.8 per cent, a total of 339 complaints, in 2021-22.

The most common complained about service areas in public hospitals 2022-23 were emergency medicine, making up 32.6 per cent, followed by general medicine (24.7 per cent), mental health care (9.3 per cent), surgery (7.3 per cent) and obstetrics (2.2 per cent).

However, the vast majority of complaints made to the HCCC about health practitioners were discontinued, 64.5 per cent, with another 15.9 per cent discontinued with comment.

Ten per cent and 19.8 per cent were referred to either the Medical Council of NSW or to another professional council, respectively.

The most common issue categories for complaints referred for investigation in 2022-23 were professional conduct, treatment, and medication concerns.

The number of complaints made to the HCCC has increased by more than 100 per cent over the past decade, which it says is driven by population growth and ageing, new and emerging health concerns, the expanding types of health services and alternative therapies on offer, greater consumer expectations and access to medical information through the internet and social media, and growing awareness of complaints bodies.