NSW doctors are outraged by a new union advertisement calling for a royal commission into the the state's health budget, saying the campaign is a "cheap sucker punch" to hardworking medicos.

The Health Services Union advert set to launch on Sunday says the health sector is failing to meet its own benchmarks despite gaining one-third of the NSW budget.

The TV ad cites recent Bureau of Health Information statistics, including that more than half of ambulances arrive later than the recommended 15 minutes, and that regional patients are waiting up to six months to see a specialist.

The 30-second piece appears to show a man suffering from a heart attack as he waits for an ambulance.

It also depicts a faceless doctor putting a wad of cash into his pocket, and a Mercedes Benz with a personalised licence plate reading DOCTOR1.

Australian Medical Association NSW president Michael Bonning said the ad was outrageous and harmful.

"The HSU's insinuation that doctors would stand idly by while patients suffer is a disgusting attack on the reputation of all doctors," he said.

"It is a cheap sucker punch to every hard-working medical professional in the state."

Dr Bonning said he found it unfathomable that the union could find it to be a fair depiction of doctors.

The state government made a record $33 billion investment in the sector in its June budget, adding $2.8 billion to $30 billion in recurrent funding.

The union's secretary Gerard Hayes said that money is not going to paramedics, therapists, radiologists and other health workers whose "incomes are going backwards".

"Only a full royal commission with the power to discover documents and compel witnesses will show us where and how the health budget is being spent," he said.

It comes after months of strikes and industrial action from nurses and health sector workers, who have calling for better conditions and nurse-to-patient ratios in NSW hospitals.

Healthcare professionals should be a team, Dr Bonning said, and not resort to "fighting for scraps from the government".

"This outrageous campaign pits healthcare workers against each other and does more harm than good."