Patients seeking treatment at Hunter emergency departments faced waits of up to four hours when arriving by ambulance this week, paramedics say.
They say this problem - known as ambulance ramping - is worsening.
The latest Bureau of Health Information data - released this week for the January to March quarter - confirms this.
Only 71.1 per cent of patients were transferred from paramedics to emergency department staff at hospitals in the district within 30 minutes, the lowest on record.
At John Hunter Hospital, this figure was 62.5 per cent - also the lowest on record.
Brendan McIlveen, a Newcastle-based paramedic, said there were "major delays" for paramedics getting patients into Hunter hospitals.
Mr McIlveen, an Australian Paramedics Association NSW assistant secretary, said this problem had been "horrendous every single day" over the past week.
"There were times when there were 16 ambulances waiting at John Hunter. I know of at least eight at Maitland at any one time," he said.
"That's related to the change in the weather, the new flu strain that's kicking in and COVID has kicked in again."
He said the "overarching issue" was that "people can't get access to GPs".
"The next quarter's results will be interesting. That will reflect this week's situation," he said.
The latest data showed one in 10 patients waited in an ambulance for longer than one hour and 21 minutes, before being transferred to emergency in Hunter New England hospitals - the worst result on record.
At John Hunter, this figure was one hour and 40 minutes - also the worst result on record.
Paramedics said these figures appear to reflect the wait for their patients to get triaged. They said the wait to transfer patients to beds was longer.
Mr McIlveen said the wait was "more like two to four hours, especially this last week".
Hunter paramedic Jodie House agreed.
"Our transfer of care is when we hand our patients to the nurses in charge of the beds they will get," she said.
Mr McIlveen added that after triage "we're moved down to the back halls to wait with patients on a bed".
HSU NSW secretary Gerard Hayes said "bed block is an unfortunate symptom of misallocation of resources in our hospitals".
"When paramedics are waiting hours to admit a patient to emergency, it's because the hospital is clogged up," Mr Hayes said.
"Too little has been invested in the wardspeople, admin workers, therapists and radiographers that keep patients smoothly moving through a hospital."
He said the NSW special commission of inquiry into health spending should "get to the heart of this problem and come up with strong recommendations".
Arrivals by ambulance to hospitals in Hunter New England in the quarter numbered 28,620 - the second highest on record.
"Our workload has increased, but there's been no major increase in funding for health," said Ms House, an HSU ambulance division delegate.
"When I put my uniform on, 80 per cent of the time I don't get home until my kids are in bed."
Mr McIlveen said the doctors and nurses were "doing everything they can".
"It's clear there are no surge plans to ramp up, as a lot of hospitals don't have the staff."
He added that John Hunter was doing an "incredible job" to get through so many cases.
A Hunter New England Health statement urged people to "support us by saving emergency departments and ambulances for saving lives".
"If an illness or injury is not serious or life-threatening, we encourage people to call Healthdirect Australia on 1800 022 222 for 24-hour telephone health advice."
The statement said public hospitals in the district "continued to deliver safe, high-quality care, despite record demand for high-level emergency care".
"We would like to acknowledge our staff for their ongoing dedication."
The district had strategies to improve, including a "focus on recruitment and dedicated patient experience officers in our larger emergency departments".