Rupert Murdoch's media empire in the US has siphoned off $4.5 billion of cash and shares from his Australian media businesses in the past two years, virtually tax free.

According to calculations by University of NSW accounting academic, Jeffrey Knapp, over the past 10 years, Mr Murdoch's companies here have paid income tax equivalent to a rate of 4.8 per cent on $6.8 billion in operating cash flows, or just 10 per cent of operating profits.

According to an UNSW academic, Rupert Murdoch's Australian companies have paid income tax equivalent to only 10 per cent of their operating profits. Credit:Reuters

News Corp Australia chief executive Julian Clarke is scheduled to appear before the Senate Inquiry into Corporate Tax Avoidance this week along with executives from Google, Apple, Glencore, Rio Tinto, BHP and Fortescue. The inquiry has been called to address rising community concerns that multinational companies are not paying their fair share of tax in Australia.

Two pages of detailed questions were put to News about its accounting practices. The response from a spokesperson for the company was: "Our financial reports comply with Australian Accounting Standards and the Corporations Act 2001, have received an unqualified audit opinion and are filed with the regulator, ASIC. Beyond this we have nothing further to add."