As people in NSW wait longer than ever for ambulances and patients face prolonged delays before being treated in hospital, Labor says chronic underfunding has led to a degradation of public health services.

The latest Bureau of Health Information Quarterly Report, released on Wednesday, reveals an under-pressure healthcare system stretched by a winter wave of COVID-19 on top of a rampant flu season.

The upshot was a blowout in wait times across the sector between April and June, with Labor blaming a decade of understaffing and poor resourcing for the troubling statistics.

"It is becoming very tiresome that we have a government who blames COVID for everything," Labor's health spokesman Ryan Park told reporters on Wednesday.

"That is not going to get to the heart of the problem."

If he becomes health minister after the March election, he will focus on resourcing and staffing, rather than ribbon cutting and opening new buildings, he said.

The major issue was the lack of staff, Mr Park said, with ample evidence of the problem presented during the recent rural health inquiry.

NSW Labor has refused to commit to implementing nurse-to-patient ratios, wanted by the nurses union.

According to the latest data, a typical patient faced a lengthy wait for an ambulance and more than 76,000 people left emergency departments without finishing treatment or being seen by a doctor - the most since reporting began 12 years ago.

One-in-five patients who leave the ED before completing treatment is likely to return within three days, bureau acting Chief Executive Hilary Rowell said.

The report found about 60 per cent of patients were seen on time, a record low for the state.

Emergency visits were up 5.2 per cent from the same period before the COVID-19 pandemic in 2019, but had fallen from a record high in 2021.

President of the AMA NSW Michael Bonning said the results were more damning every quarter, and it is time for the Commonwealth to commit to a 50-50 funding split with the state government.

"We can't keep doing the same things and expecting to see improvements," Dr Bonning told AAP.

"People have gone to superhuman efforts and lengths to manage the COVID-19 waves and the influenza season, and the respiratory viruses.

Those efforts could not be sustained and NSW risked losing much of its workforce to burnout, he warned.

General Secretary of the NSW Nurses and Midwives' Association Shaye Candish said the findings were a reflection of the extreme pressure placed on healthcare staff.

"The sheer volume of patients leaving our emergency departments before starting their care is shameful," she said.

However, NSW Health maintained that despite the stress of COVID-19, the flu and furloughed staff, hospitals performed well and delivered high-quality care during the winter period.

"We continued to make every effort to ensure that those who needed care urgently received it without delay," Deputy Secretary Matthew Daly said.

Ambulances were also in high demand with patients facing record average wait times.

Half the ambulances sent to patients classified as "emergencies" took more than 16.3 minutes, the worst result in 12 years.

More than half (57.6 per cent) the ambulances sent to life-threatening emergencies arrived within the benchmark 10-minute timeframe, also the worst result in 12 years.

Wait times for non-urgent elective surgery is also on the rise, with more than 26,000 people who had surgery in the quarter having waited just under a year.

President of the NSW branch of the Australian Paramedics Association Chris Kastelan said the situation was deteriorating.

"We're alarmed that response times are growing longer every quarter," he said.

"When transfer of care times blow out, paramedics are left waiting outside hospitals and unavailable to respond to emergencies in their communities.

"It's incredibly concerning."