Julie Williams has been a speech pathologist in the NSW public health system for 36 years.
But under her current agreement, she says she is paid about the same as some fresh graduates working in private practice.
The chronic undervaluing of her colleagues meant they had been leaving the public system in droves, she said, putting even more pressure on the workforce.
“The cost of living is making it impossible for them to stay here,” the head of speech pathology at the Hastings Macleay Clinical Network told AAP.
“We can't retain our staff, so our workload increases.”
Ms Williams, who is based in Port Macquarie, is one of the 27,000 allied health professionals across the state being represented in a case that begins in the NSW Industrial Relations Commission on Wednesday.
The Health Services Union is pushing for a 20 per cent pay rise for allied health workers across 40 professions within NSW Health.
It is also pushing for a major shift in the conditions, structures and classifications of allied health workers to reflect how their roles have changed over time, with many now qualified to do work previously done only by doctors.
Ms Williams said she and her colleagues had undertaken extra study to perform nasendoscopies - a procedure that involves a camera being inserted into a patient's nose - which was previously done by ear, nose and throat specialists.
This meant patients spent less time in hospital and less time on specialist waitlists, saving the government money.
"And that hasn't been really fairly recognised," Ms Williams said.
The case, if successful, is also set to be a major win for the gender pay gap.
Because women make up 90 per cent of the workers in the claim, the union will argue the workforce has been subjected to gender-based undervaluation.
“Pretty much any caring work is highly feminised work,” Ms Williams said.
“And the pay does not recognise the amount of qualifications that we have, the amount of accountability we have, the level of emotional resilience that you need to have working in this kind of a job.”
Union NSW Secretary Gerard Hayes said 150 witness statements had been gathered as part of the “generational” case.
“These allied health professionals have been underpaid for years and it’s beyond time their value and productivity was properly recognised,” he said.
The hearing, which is set to run until February 2027, will lead to the first value assessment of allied health workers since 2007.
Premier Chris Minns has already committed to fully funding whatever the commission’s ruling is - a pledge Ms Williams welcomed.
"We see that as recognition by the government that ... we have a good case here," she said.
