Two former Victorian government ministers have been appointed to plum public hospital posts, rankling Liberal MPs amid a probe into the politicisation of Victoria's public service.

Former health minister Martin Foley and ex-police and emergency services minister Lisa Neville have been appointed as board chairpersons of Alfred Health and Barwon Health respectively.

They will begin their roles on July 1, along with 234 newly appointed directors.

Health Minister Mary-Anne Thomas announced the appointments in state budget estimates on Friday, sparking indignation from the Public Accounts and Estimates Committee's deputy chair Nick McGowan.

"Here we go - wow," the upper house Liberal MP said before being accused of childish interjections and grandstanding by chair Sarah Connolly.

Mr Foley and Ms Neville were among five senior Andrews government ministers to retire at the state election in November.

Ms Thomas replaced Mr Foley as state health minister 12 months ago, while Ms Neville cited a long-running fight with Crohn's disease for her decision to step down from cabinet and quit politics.

Opposition health spokeswoman Georgie Crozier took aim at the government for appointing their mates to plum board roles instead of addressing problems in the health system.

"Our health system remains in crisis," she said.

But Ms Thomas maintained consideration was given to the board's skills, capabilities and balancing renewal versus stability.

"One has to ask whether the same could be said of the appointments under the previous government," she said, citing a list of former Liberal MPs to be appointed to prominent public sector posts.

"You've got to be kidding," Mr McGowan said.

Ms Thomas replied: "Perhaps you can explain (former opposition leader) Robert Doyle's appointment?"

The Victorian Ombudsman is investigating if the state's public service has been compromised by the hiring of more than 30 former advisers to Premier Daniel Andrews and his ministers.