Electromagnetic interference from the $14 billion Metro Tunnel is still wreaking havoc on sensitive medical equipment at Melbourne's dedicated cancer centre.
The long-running rail project will connect the busy Sunbury, Cranbourne and Pakenham lines through a new tunnel under the city and is expected to open in 2025.
But a leaked document published by The Age reveals MRI scanners at the Peter MacCallum Cancer Centre near the new underground Parkville station failed equipment tests in June.
The issue of electromagnetic interference (EMI) has reportedly cost $128 million in capital works across Peter Mac, Royal Women's and Royal Melbourne hospitals.
Premier Jacinta Allan said EMI risks were identified from the outset of the project but the scale of the problem became clear when test trains began running through the tunnel in mid-2023.
"It was at that point that we could test the mitigation measures around the hospitals particularly," she told reporters on Wednesday.
"No patient care has been compromised."
In May, the Allan government abandoned building a medical precinct in the new suburb of Arden after technical work showed EMI from a Metro Tunnel underground station could disrupt sensitive medical equipment.
A report from the auditor-general in June stated further work was needed to address the impact of EMI at six institutions near the Parkville and State Library stations.
Peter Mac, the Royal Melbourne Hospital, Royal Women's Hospital, University of Melbourne, Peter Doherty Institute and RMIT University were the six institutions listed.
In a temporary solution, Peter Mac moved its MRI services to its East Melbourne centre and Royal Melbourne's new MRI department.
A more permanent solution trialled involved testing magnetic active cancellation systems (MACS) to address the remaining risks on the machines at Peter Mac and the Royal Melbourne Hospital.
The report said testing in April showed "inconclusive results" on the effectiveness of MACS and Rail Projects Victoria planned further testing for June 2024.
The Metro Tunnel was originally costed at $10.9 billion when announced in 2016 but has blown out to $12.8 billion for taxpayers and $14 billion overall.
The same auditor-general report revealed its contracted completion date of September 2024 would not be met and the state would need to pay more to address remaining issues.
Ms Allan said funding for mitigation was contained in the project's original budget but dodged questions over whether enough cash was set aside.
Opposition Leader John Pesutto said the burden of the "massive debacle" would fall on patients and taxpayers and suggested the government didn't do enough due diligence.
"You do the work before you commit to a project," he said.