South Australia's Opposition says maggots, flies and earwigs have been discovered in meals served to patients at the Flinders Medical Centre in Adelaide's south.

Key points: ISS took over catering at the Flinders Medical Centre last year

ISS took over catering at the Flinders Medical Centre last year Since then, SA Health has received 600 complaints about the food there

Since then, SA Health has received 600 complaints about the food there SA Health says it is improving and complaints are down

Labor says documents released by SA Health under Freedom of Information show the hospital received more than 600 complaints about food last year.

As well as insects and larvae in food, complaints included raw or undercooked fish and chicken, a Muslim woman being served and eating pork by mistake, wrong orders arriving and unappealing-looking food.

"If patients are at their most vulnerable, they're sick and they start getting meals that have got maggots in them or uncooked chicken or relatively raw fish, then we've got a massive problems to that person's health and wellbeing," Opposition Leader Peter Malinauskas said.

One man complained about receiving two party pies for dinner each night.

A meal, possibly meatloaf and mashed potatoes, served to a patient at the centre. ( Supplied )

Mr Malinauskas refused to blame contractor ISS, which took over food services at Flinders last year, instead blaming State Government cuts.

State Budget documents show SA Health plans to save $4.5 million per year from 2020–2021 by "standardising the delivery of hotel services at SA Health sites".

Mr Malinauskas said the number of complaints was an "astonishingly appalling result" and showed the cuts should be reversed.

"No-one expects silver service, but I think what people do rightly need and rely on is a healthy meal to help their recovery as soon as possible," he said.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 15 seconds 15 s A pudding served to breast cancer patient Cheryl Hewick at the hospital last year.

SA Health says meals are improving

In a statement from SA Health, a Southern Adelaide Local Health Network spokeswoman said: "Flinders Medical Centre commenced a new catering contract with ISS in May 2019 and we are aware that there were some teething issues during this transition.

"We are pleased to say that we have worked closely with ISS to improve the quality and timeliness of meals, and have significantly reduced the number of food related complaints as a result.

"We apologise to any patients who were inconvenienced during this time."

Flinders Medical Centre is in Adelaide's southern suburbs. ( ABC News: Leah MacLennan )

Opposition health spokesman and southern suburbs MP Chris Picton said Flinders had been well known for its good food, but it was now "disgusting".

He said it was "hard to imagine that this could get worse but sadly with more cuts, more corners are going to have to be cut".

"Where you see earwigs in food, where you see flies in food, that's not acceptable and it shows these cuts need to stop," he said.

"We're worried that if the cuts continue even more from July 1 that we will see more of these reports and patients will suffer more."

The Royal Adelaide Hospital has suffered similar complaints about food, however its catering falls under a different contract.

A unappealing sandwich served at the hospital. ( Supplied )

Patient won't go back because of service

Cheryl Hewick had several surgeries at the Flinders Medical Centre after being diagnosed with breast cancer.

She said the meals were "atrocious".

A casserole served to a patient at Flinders Medical Centre. ( Supplied )

"They were in such condition that most of the ladies couldn't eat," she said.

"Their husbands and partners were bringing food in for them constantly.

"It was of such quality that you couldn't cut the food, you couldn't eat the salmon patties — everything was hard, everything was dry, everything was very tasteless and incredibly salty…

"They wouldn't even serve it to their dogs."

Ms Hewick chose not to have another reconstruction surgery because of the "horrid" food.

"One reason I just dread going there is because you have nothing to look forward to except going home," she said.

A State Government spokesman said the 600 complaints came from 600,000 meals delivered by ISS.

"While we would like that number to be zero, we need to keep in context — about 1 person in every 1,000 meals lodged a complaint, and many of the complaints were borne out of teething issues from the transition to a new provider and have since eased," he said.

The ABC contacted ISS by phone and email but has yet to receive a response.