Billionaire James Packer has resigned as a director of Crown Resorts for mental health reasons.

He is "suffering from mental health issues," a spokesperson from Consolidated Press Holdings, another of Mr Packer's companies, confirmed.

"At this time he intends to step back from all commitments."

Crown's executive chairman John Alexander said in a statement: "We have appreciated James' contribution to the board and respect his decision to step down from his role as director at this time."

Earlier this month, Mr Packer sold more than $100 million worth of his shares in Crown Resorts, which owns the Crown casinos in Melbourne and Perth.

He remains the major shareholder of Crown, with a 47 per cent stake worth more than $4 billion.

It's not his first resignation

It is the second time that Mr Packer had left the company's board.

He previously resigned as a director in December 2015 to focus on development projects in Melbourne and Las Vegas.

This was in addition to him overseeing the development of the newest Crown casino at Barangaroo, Sydney — which is currently under construction.

Mr Packer rejoined the board in January 2017, several months after staff from Crown's sales and marketing team were arrested in China.

His personal life has been in the spotlight in recent years — from his public break-up with American singer Mariah Carey, to being questioned by police as part of an investigation into the alleged corruption of Israel's Prime Minister Benjamin Netanyahu.

On top of that, Crown is facing potential disciplinary action from the Victorian Commission for Gambling and Liquor Regulation, which could result in its casino licence being suspended.

This was after the commission investigated claims from whistleblowers that Crown restricted punters' options by removing buttons on several of its poker machines.

Crown Resorts experienced a knee-jerk reaction to Mr Packer's resignation, with its share price dropping by 1.7 per cent in the first few minutes of ASX trading.

The company's stock market losses have since moderated, down 0.7 per cent to $12.98 about 11:00am (AEDT).