Both have formed special committees to review proposals of a potential combination, they said on Friday.

If a deal goes through, the combination will allow Murdoch greater control over his media assets and help the companies trim costs.

Media companies are fighting decades-low growth in advertising sales and for users' attention against deep-pocketed social media and content websites.

After years of expansion globally, Murdoch split his empire in 2013, placing the print business in newly created public entity News Corp and the TV and entertainment under 21st Century Fox.

The thinking at the time was that this would generate more value for shareholders, according to one person familiar with the decision-making. That vision was realised as Fox sold the bulk of its film and television assets to Walt Disney Co for $US71 billion ($A113 billion) in 2019.

The media landscape has changed radically in the years since Murdoch separated his media holdings, with technology companies such as Apple Inc and Amazon.com Inc playing a significant role in distribution and bidding for sports rights.

It make sense, in this context, to reunite Fox and News Corp to create a company with complementary assets and greater scale, the person familiar with the proposal said. The combined companies would have around $US24 billion ($A38 billion) in revenue.

Murdoch, 91, has near-controlling stakes in both the companies. His son Lachlan Murdoch is chairman and CEO of Fox Corp.

As of market-close on Friday, News Corp had a market cap of $US9.31 billion ($A14.83 billion) and Fox Corp was $US16.84 billion ($A26.82 billion), according to Refinitiv. News Corp shares surged five per cent and Fox rose about one per cent in after-market trade.

The development was first reported by the Wall Street Journal earlier in the day.

Australian Associated Press