Billionaire James Packer has resigned from 22 Australian company directorships in the past few weeks and no longer holds any board seat in his home country, corporate records show, signalling his almost full retreat from public business life.

The major shareholder of casino operator Crown Resorts cited mental illness as the reason for quitting that firm's board in March, following a tumultuous period in his life, which included a break-up with singer Mariah Carey and the failure of Crown's expansion strategy.

He quit the board of his private company Consolidated Press Holdings (CPH) on June 27, and corporate records show he resigned from 19 other directorships on the same day, plus another two since.

Mr Packer, whose net worth is estimated by Forbes at $4.1 billion, has quit 24 Australian company boards this year.

"The changes are largely administrative in nature and reflect attempts to modernise and simplify the corporate structures," a spokesman for Mr Packer's flagship CPH said by email.

Packers were fixtures of the media business scene

His retreat is all the more remarkable because, for generations and most of the 20th century, the Packer family has been a fixture of Australia's media business scene.

The 50-year-old is one of Australia's highest-profile businessmen and a household name who has previously served on the boards of some of the country's biggest companies, from Qantas Airways to Nine Entertainment and Seek, where he was an early investor.

Mr Packer's father, Kerry, inherited media interests from his own father, Frank, in 1974 and built them into a publishing and television empire, which James sold a decade ago in order to form Crown, a casino firm.

He built it up before quitting as a director in 2015 amid a heavily publicised personal upheaval, including a brief engagement to Carey.

Mr Packer re-joined Crown's board a year later during a period of turmoil for the company when a dozen and a half of its employees were jailed in China for alleged breaches of gambling marketing laws there.

"Mr Packer is suffering from mental health issues. At this time he intends to step back from all commitments," CPH said in March when Mr Packer quit Crown's board.

The Australian newspaper, which first reported Mr Packer's string of resignations, said he remains a director of CPH's parent company, Consolidated Press International Holdings Limited, domiciled in the Bahamas.

Reuters