Cancer patients and survivors say they fear people will die waiting for the peritonectomy surgery as waiting lists grow because of the cuts.

The surgery, which involves removing cancer from a large part of the abdominal area, is the only hope of a cure for some cases of the deadly asbestos cancer mesothelioma.

St George Hospital is the only place in NSW that performs it.

A world expert and pioneer of the procedure, David Morris, had been operating for three days a week at St George but has been forced to cut his operating days to two due to the growing surgery demands across the hospital.

"We were already struggling to get our patients treated," he said. "We already have 20 patients who have been waiting longer than the clinically recommended limit."

That time limit ranges between one and three months, depending on the patient.

Patients are flown from all over Australia and New Zealand to be treated by Professor Morris and the surgeon fears things are only going to get worse.

"I'm very worried people are going to progress and then be inoperable," he said.

People in need of cancer surgery should be prioritised over other patients if there was a shortage of money, he said.

Cancer patient Teressa Browne, 61, said the three months waiting for the surgery was extremely hard on patients and their families.

"It's a horrible feeling," she said.

The wife and grandmother of five said until she found out about Professor Morris she and her family worried nothing could be done for her.

This week she was told she is likely to finally get her surgery on Tuesday.

"Now I have got a bit of hope, but it's very hard to keep hope when you are waiting," she said.

St George Hospital said the cuts were necessary because without them the waiting list for other cancer surgeries would blow out.

"When reviewing surgical caseload for St George Hospital, the Clinical Council - which consists of clinicians, specialists and senior staff - is required to balance the needs of all surgical patients across all specialities to ensure patients are being treated within their clinically appropriate assessed time," Cath Whitehurst, the director of operations at St George, said.

But the opposition health spokesman, Andrew McDonald, said the decision had been taken because the hospital was underfunded.

"They are refusing to do it because of money, it's a simple as that," he said.

"They have got the surgeon who is ready, they have got the physical space and they have got the staff … they just don't want to pay them".

According to Mr McDonald it was wrong to say that continuing to perform the surgeries would put other patients at risk.

"They could easily increase their capacity within their built space to do the surgeries and not make people wait, they just haven't got the resources," he said.

A peritonectomy is used in peritoneal mesothelioma, which accounts for about a quarter of all mesothelioma cases, as well as in cancers of other areas such as the liver.

Ms Whitehurst said St George was already funded to do 72 peritonectomy surgeries every year, which was more than was needed given the population of NSW.

"At present peritonectomies are not offered in all states," she said.

The hospital did have some capacity to run some extra peritonectomy surgeries in emergencies, Ms Whitehurst added.