Mr Murdoch moved late last week to tone down the more controversial aspects of the proposal in the face of fierce opposition from Australian and American investors, but he still faces an uphill struggle. One big US pension fund - for Californian state employees - said that any plan involving differential voting rights would be opposed.
The London Stock Exchange is also expected to oppose the revised plan.
Rowan Ross, president of the Securities Institute of Australia, which represents 5,500 professionals in the securities and banking industries, described super voting shares as 'an unacceptable precedent'. The institute is conducting a poll of its members on the issue.
Mr Ross called on the Australian Stock Exchange to retain its existing rule of 'one share, one vote,' and said: 'The debate on super voting shares goes to the heart of the whole concept of corporate control, proprietorial rights and the enfranchisement of ordinary shareholders. Some members believe that super voting shares will entrench the control of a single shareholder and effectively dispossess ordinary shareholders of their rights.'
His remarks are mirrored by the Australian Investment Managers' Group, which represents 48 of the country's big institutional fund managers. Its members account for more than Adollars 250bn ( pounds 110bn) of share market funds, including about one- fifth of News Corporation's stock.
The group resolved that any departure from the principle of 'one share, one vote' by the introduction of super shares 'would set a dangerous precedent'. Its chairman, Peter Griffin, of Rothschild Australia Limited, said: 'Australian investors and the Australian economy cannot afford precedents to be introduced into securities markets that would bring about a diminution of the integrity of those capital markets and therefore the capability of Australian companies to raise money on world competititive terms.'
He added: 'The proposal . . . appears to be a device to bypass the existing legislative requirements. We believe the Australian Securities Commission (the corporate watchdog) should be directing their attention to the proposal.'
Mr Murdoch's scheme is aimed at securing long-term control of News Corp at a time when the company is poised to enter strategic alliances with other big players in the world communications industry. He would be able to issue shares for acquisitions without significantly diluting his own family's 32.7 per cent position in the stock, thus avoiding a repetition of the massively debt-funded expansion that almost sank his empire three years ago.
In America, many pension funds have rules preventing them from voting in favour of proposals that inhibit takeover bids. For example, one large fund, the California State Teachers Retirement System, specifically rules out companies proposing 'golden parachutes, poison pill preferred schemes, lock-up options and super-majority voting provisions'.
According to one fund manager, at least some US funds could be neglecting their fiduciary responsibilities if they went along with the proposals.
One UK fund manager commented on the proposal: 'I suppose I'm against it in principle, even for Murdoch' who, he said, had done a fantastic job for News Corp shareholders.
Mr Murdoch, the chairman and chief executive of News Corp, unveiled the plan at the annual meeting in Adelaide last month. The idea, he said, was to 'create the opportunity to increase our capital base through equity infusions which may arise from new and major strategic alliances'.
He gave few details of the scheme, but its essence would be to issue new bonus shares to existing shareholders which would carry a 'super' voting right of 25 votes as opposed to the single vote held by ordinary shares.
The element that aroused most criticism was that the ''super' votes would revert to a single vote once a super share was sold. Mr Murdoch has backed off from this and other more controversial elements of the plan, but even the revised proposals have failed to appease international investors.