Junior doctors at Canberra Hospital and Calvary Public Hospital have launched a class action law suit in the Federal Court.
Current and former doctors claim they were systemically underpaid for unrostered overtime.
The class action could include more than 1500 doctors, including medical interns, resident medical officers and registrars, lawyers representing the doctors said.
Junior doctors said they are concerned about the safety of patients in the care of overworked and exhausted medical staff.
They are being represented by Hayden Stephens & Associates, which also represents junior doctors involved in similar suits in NSW and Victoria.
Junior doctors in Canberra are working up to 25 per cent more than their rostered hours, lawyer Hayden Stephens said.
"Underpayment of unrostered overtime is systemic and widespread," he said.
"[It] has been going on for several years.
"These junior doctors straight out of university are often in a far more vulnerable position than say, senior doctors. Hospitals run on a culture of a very strict hierarchy.
"That is an environment in which hospitals are clearly taking advantage of junior doctors."
Mr Stephens said all junior doctors working within that six year period would automatically be part of the class action suit, unless they actively opted-out.
"The timespan in which the claim covers is six years. So whilst we don't have a precise number of doctors that will form part of the class, it would appear that on those numbers alone it would be in excess of 1500, quite possibly higher," he said.
"If you have regard to the number of doctors who will form part of this class, the number of hours that they've worked unpaid, and the six year period in which the claim covers, then I would expect that [the payout would be] significant."
Former Canberra Hospital and Calvary Public employee Dr Betty Ge said she would sometimes work 16 hour shifts as a junior doctor.
She said she would sometimes finish at 10pm, then start at 6am the next day.
Dr Ge said the class action suit was "never about the money".
"The suicide rate in the medical industry is quite high, and I think part of it is because we work such long hours," she said.
"I want to see a safe and a fair working system for the junior doctors, want to protect my future generations of medical practitioners because I see a lot of juniors really struggling with their own wellbeing."
Dr Ge said while doctors were "ready for hard work", patients were put at risk.
"[Making] the comparison to the aviation industry, you wouldn't want your pilot to work really tired, hungry, with low morale," she said.
"[Similarly], you wouldn't want a junior doctors to be overtired ... It's not safe for the junior doctors, and it's not safe for the patients.
"We're more prone to make mistakes."
Dr Ge completed her residency at The Canberra Hospital and Calvary Hospital for two years in 2020 and 2021.
She said different rotations would be better or worse for overtime.
"I think in terms of overtime, probably more surgical rotation. And certainly in terms of the general surgery, obstetrics, surgical rotations involving procedures will be very busy," Dr Ge said.
She said it was hard for juniors to speak out, because the opportunity to be selected for competitive specialist programs relied on the support of supervisors and senior doctors.
"It's actually quite hard to get people coming forward to speak about these issues because it's such a deep, long lasting issue that's ingrained in the culture of medicine," she said.
"But as a matter of fact, we know it's not really safe."
A spokesperson for Canberra Health Services said: "we acknowledge that 2022 has been a particularly challenging time for many of our junior doctors.
"Junior Doctors at CHS are paid for worked overtime as per the ACT Public Sector Medical Practitioners Enterprise Agreement 2021-2022.
"Regular reviews of team member workloads, including junior doctors, are undertaken."
A spokesperson for Calvary Health Care said patient and staff safety was the number one priority at Calvary Public Hospital.
"Calvary Public Hospital Bruce has been delivering high quality, safe and compassionate care to Canberrans for more than 40 years," they said.
"Patient safety, together with care for our valued staff, continues to be our number one priority. We are committed to supporting our junior medical officers and all of our medical and health workforce."