A family battle over the future of Rupert Murdoch's media empire – including most of Australia's capital city newspapers – has begun in a court in the US state of Nevada.

The Australian-turned-American press patriarch and four of his children have travelled to the desert city of Reno, where a court is considering the future of a multi-billion-dollar family trust.

Rupert, 93, wants to amend the trust to ensure his eldest son, Lachlan, retains control of his companies, News Corp and Fox Corp, when he dies.

To do so, he needs to change the trust's "irrevocable" terms. The terms, as they are currently written, would split control of News and Fox between Lachlan, who chairs both companies, and three of his siblings: James, Elisabeth and Prudence.

The trio is opposing the move to change the terms of the trust.

Former US attorney-general Bill Barr, who served presidents George HW Bush and Donald Trump, is representing the elder Murdoch in the court dispute.

The Succession-style drama has been playing out in secret for months. It was exposed in July when the New York Times obtained a confidential court document. 

The court documents have been kept confidential, and the court hearings are closed to media and the public.

But about 20 journalists and six camera crews greeted the Murdoch family members as they arrived at Reno's Second Judicial Courthouse.

The first convoy of luxury SUVs pulled up just before 8am on Monday, local time. 

Billionaire siblings James, Prudence and Elisabeth arrived together, though in separate vehicles. James was accompanied by his wife, Kathryn, and Elisabeth by her husband, Keith Tyson.

All ignored questions from the assembled press as they made their way up the courthouse staircase.

About half an hour later, Rupert and Lachlan arrived in a separate convoy.

Rupert, holding the hand of his new wife Elena Zhukova, acknowledged the media with a nod of his head but made no comment.

Lachlan was also with his wife, model and former TV presenter Sarah Murdoch. They appeared relaxed as they chatted to each other but pointedly also ignored the media. 

Family politics

According to the Times, Rupert wants his companies to remain a politically conservative media force after his death. The court documents note his concern that a "lack of consensus" among the siblings "would impact the strategic direction at both companies including a potential reorientation of editorial policy and content".

Lachlan, who is currently the CEO and executive chair of Fox Corp and the sole chair of News Corp, is understood to be more aligned with his father's right-wing politics than the other three siblings. 

Changing the terms of the family trust would avoid a possible three-against-one voting split – with younger brother James aligned with sisters Elisabeth and Prudence – which could see Lachlan stripped of control. 

"Lachlan wants to keep his job, that's what this is about," said author Michael Wolff, who has written books about the Murdochs and Fox News. "Lachlan will lose his job when his father dies as things now stand – the entire legacy will be overhauled as soon as Rupert dies."

James resigned from News Corp's board in 2020 after criticising its Australian outlets' climate coverage, including the "ongoing denial of the role of climate change" in devastating bushfires that year.

Earlier this month, he was among 88 American corporate leaders who signed an open letter endorsing Democratic candidate Kamala Harris for president. 

He is known to have strong reservations about Fox News' promotion of Donald Trump's election-theft conspiracy theories, which cost the company more than $US787 million ($1.2 billion) after it was sued for defamation by a voting-machine company. 

"I think you can characterise the three children as liberal, cosmopolitan, internationally oriented, at best moderate in their politics, but certainly not right-wing in their politics," said Wolff.

"I think they have been appalled by what Fox News has become and what it has done to American politics."

James is reportedly not on speaking terms with Lachlan or Rupert. James, Elisabeth and Prudence also did not attend the wedding of Rupert and his fifth wife, Elena Zhukova, last month.

Behind closed doors

In order to amend the terms of the "irrevocable" family trust, which was set up 25 years ago, Rupert must show the amendments have the sole purpose of benefiting all its members.

The trust's members are the four siblings as well as Rupert's youngest daughters, Grace and Chloe, from his third marriage.

He is arguing, according to the court document cited by the New York Times, that keeping Lachlan in control and thereby keeping the politics of the media outlets unchanged, he is protecting the companies' commercial value. He also wants to prevent future leadership disputes hurting the companies.

Other media outlets – including the Times, Washington Post, CNN, Reuters and Associated Press – applied to have the court hearings opened, and the confidential documents "unsealed" to make them publicly available, but were unsuccessful. 

A Nevada-based organisation that monitors the performance and error rates of the state's judges and courts, Our Nevada Judges, also applied to have the hearing opened. 

Its founding director, Alex Falconi, said there was a "culture of secrecy" in the Nevada courts, particularly relating to family disputes.

News Corp owns seven of Australia's 12 national and capital-city daily newspapers, and its online-only outlet, news.com.au, generally tops readership ranking lists. 

Its dominance of the print media market, and the nature of some of its campaigning journalism, has seen it branded a "cancer on democracy" by Kevin Rudd, and an "absolute threat to our democracy" by Malcolm Turnbull. 

The former prime ministers called for an inquiry into the Murdoch media in 2020. A subsequent year-long Senate inquiry found News Corp was "a troubling media monopoly", and pointed to its newspapers' "decade of campaigning against the science of climate change" as an example of its influence on government policy. 

It also owns Sky News Australia, which has an "after-dark" roster of right-wing commentators similar to that of Fox News. 

The family trust case is being heard by a probate commissioner – a court official who makes recommendations to be signed off by a judge. 

An evidentiary hearing is set down for seven days.