Liberty Media, the US cable TV and investment group, is finalising a compromise deal with News Corp that would remove a potential threat to Rupert Murdoch's voting control of the US media and entertainment company.

John Malone, Liberty chairman and chief executive, is understood to have offered to assign rights over Liberty's almost 19 per cent voting stake in News Corp - accumulated at the end of last year - to Murdoch family interests.

The shareholder agreement is expected to form part of an "outline deal" between the two companies, easing concerns that Liberty could challenge the Murdoch family's 29 per cent voting ownership of News Corp, according to executives close to the situation.

Last year, News Corp issued a "poison pill" rights issue defence after Liberty surprised Mr Murdoch, the News Corp chairman and chief executive, by doubling its voting stake as the company prepared to shift its main stock market listing and corporate domicile from Australia to the US.

"The idea is for a voting trust in which Rupert would be able to vote Liberty Media's stock in the company," according to one person close to the proposed transaction.

The scheme is expected to mirror a proxy deal between Liberty Media and IAC, the interactive services group led by Barry Diller. Mr Diller, IAC chairman and chief executive, has authority from Mr Malone to vote Liberty's controlling stake in the interactive business.

Mr Malone has told colleagues that his "dream outcome" at News Corp would see Mr Murdoch counting on Liberty's voting support, while Liberty shareholders could receive a distribution of News Corp stock.

The possible stock distribution is the subject of continuing talks between News Corp and Liberty.

This week, Mr Murdoch expressed confidence that an agreement with Liberty would be made within the next three months.