Flinders University has apologised for underpaying more than 1,400 casual staff over several years, in a case the higher education union has labelled a "massive breach of trust".
The underpayments were worth $965,827 and impacted 1,405 current and former staff, the university said, equating to roughly $687 underpaid per person.
The issue occurred between 2020 and 2025, the university said.
In an all-staff email on Friday afternoon, Flinders University vice-chancellor Professor Colin Stirling said the issue was identified by a university review into payment practices for casual employees.
He said the university was now contacting affected staff, who would be repaid with superannuation and "applicable interest".
"We accept responsibility for it, and, on behalf of the University, I sincerely apologise to all those affected," Professor Stirling wrote.
The National Tertiary Education Union (NTEU) SA said the underpayments affected professional, non-academic staff who were "precariously employed, low paid [and] predominantly women".
The university says it disputes that characterisation.
The repayments will "easily" exceed $1 million when factoring in superannuation and interest, the union said.
Three-hour 'minimum engagement' clause at fault
Flinders University said the issue was it had not paid some casual staff their three hour "minimum engagement period".
This is a workplace clause that stipulates a causal employee must be paid for at least three hours, even if their shift ends up being shorter.
"This does not mean staff worked hours without being paid," the vice-chancellor said.
"Rather, some staff should have been engaged for a longer period of time to comply with the minimum engagement period."
Professor Colin Stirling says the university is now contacting affected staff. (Flinders University)
Professor Stirling added that not all casual staff were subject to the three-hour requirements, with "multiple exemptions" under the university's enterprise bargaining agreement (EBA).
"The issue occurred in the context of a complex enterprise agreement that includes a number of provisions and exceptions to the three-hour minimum engagement period," he said.
"While this complexity provides important context for how the errors occurred, it does not diminish the University's responsibility."
The university has now introduced stronger controls, monitoring, oversight and training, Professor Stirling added.
Underpayments 'massive breach of trust', union says
Flinders University's underpayment admission comes only a year after the old University of Adelaide revealed it had underpaid 838 casual academic staff $1.25 million over eight years.
The underpayments, which occurred between March 2017 and May 2025, were equivalent to nearly $1,500 per staff member.
NTEU SA division secretary Andrew Miller said underpayments were a "feature, not a bug" of Australia's higher education system.
He added that Flinders University's underpayments were "actually large for a small, bespoke university".
"This represents a massive breach of trust, a massive breach of entitlements and hardship for the staff throughout a period of time where there's been high inflation and cost of living pressures," he said.
The university says it accepts responsibility for the underpayment, and has apologised to staff. (ABC South East SA: Sam Bradbrook )
Dr Miller also rejected the university's reasoning around complex EBAs.
"If they can't implement the enterprise agreements that they sign, there's a big problem in the governance of our universities," he said.
"Staff are due their entitlements, and vice chancellors must ensure those entitlements are paid and honoured in full."
A spokesperson for Flinders University noted that it was the university's own review that discovered the error, which it had "disclosed publicly and apologised for".
"Affected staff are being paid as quickly as possible, including applicable interest and superannuation," the spokesperson said.
"It is important to note that all affected staff were paid in full for the work they did. The error is that these individuals should have been engaged for a longer shift."
The NTEU SA and Flinders University are currently locked in enterprise bargaining negotiations.
Union members voted last month to take industrial action, including work stoppages.