The union representing a retired nurse being sued by Queensland Health because of an administration error over her long-service leave payment, says there could be hundreds of other cases yet to emerge.

Key points: Kay Boisen has already paid back $8,000 in a separate overpayment

Kay Boisen has already paid back $8,000 in a separate overpayment Ms Boisen says she checked repeatedly with payroll before taking the leave

Ms Boisen says she checked repeatedly with payroll before taking the leave The Opposition has called on the Government to urgently fix issues with Queensland Health's new digital system

Former Bundaberg nurse Kay Boisen has been ordered to pay back about $40,000 worth of annual leave she took just before she retired in 2017.

Shortly after taking the leave, she was told she had not actually accrued it.

Jack McGuire from the Nurses Professional Association of Queensland said it was not an isolated case.

"There have been about 30 that we're aware of and we represent about 10 per cent of nurses in Queensland — but there could be up to 300," he said.

"We're launching a full throated defence. I think the situation is particularly egregious with Kay though because it was just long service leave entitlements.

"It wasn't money ending up in your bank account, it was taking a directive by your manager and saying, 'yes okay I'll take the leave', you go and take the leave and then they say 'okay now you owe us the cash'."

'This has had a huge impact on my life'

Ms Boisen — who worked as a nurse for more than four decades, including 35 years with Queensland Health — said she was also overpaid a separate amount of $8,000 during the 2010 payroll debacle, which she agreed to pay back.

But she said she was shocked when she was told she would have to pay back an additional $40,000 in annual leave payments she received in the lead up to her retirement.

"I had been offered six months of long service leave to finish as I left Queensland Health," she said.

"Three or four weeks before I was due to finish I was called in for a meeting and I was told there was a 'glitch' from 2010, which meant that all the long service leave that I'd used — and in fact all the other leave I had accrued — was all a big mistake and it wasn't there anymore."

Ms Boisen said she has appealed to the State Government for help but vowed to fight her case.

"Do I feel put upon? Absolutely," she said.

"There's no doubt that this has had a huge impact on my life — it's certainly not the carefree retirement I had envisaged for myself.

"I've had some health issues, I haven't travelled as I thought that I would, I am restricted with what I am going to spend because this is a big whack of my savings that they're wanting.

"I'm being taken to court so the next step is to plead my case."

She said she specifically checked with the payroll team before taking the leave.

"I spoke to payroll at least twice — once casually and once officially to assure me that the leave entitlements documented on my payslips were in fact true," she said.

"I gave them plenty of opportunity to resolve any issues. I put my separation paperwork in announcing my retirement eight months before I actually finished work.

"The leave that I took in the last six months before I finished work, that approval was given three months before that leave was started.

"This could have all been avoided. I was shown a data sheet where a component of my leave had the input four times [the regular amount] — back in October of 2010."

A Queensland Health spokeswoman said it would be "inappropriate" to comment on the case.

"Queensland Health does not provide comment on past employees or matters before the courts," she said.

'Show some compassion'

Deputy Opposition Leader Tim Mander called on the State Government to have "compassion" on Ms Boisen.

"Nine years later after the greatest health bungle of all time with the Bligh Government there are still people suffering," he said.

"The woman's presented a very good case that you would think would lead to some compassion."

Mr Mander also called on the State Government to urgently fix issues with Queensland Health's new digital system used to order medical supplies.

The ordering software known as S/4HANA was rolled-out last month but authorities have had to establish a specific hotline to help suppliers who are complaining about issues with the payment process.

"Some of these companies aren't necessarily big companies, they need their bills paid so they can pay their staff," he said.

"If the Government doesn't pay these bills it could lead some of these companies to go to the wall."