Scams of big four accounting firms

The big four accounting firms have been branded as aggressive, unethical, and accused of "perpetrating the greatest tax crimes in history" by a leading corporate tax authority.

At least $US1 trillion in tax revenue is lost worldwide, and $50 billion in Australia, as a result of aggressive tax minimisation schemes established by the four giant firms who audit the books of nearly all the world's major companies, said George Rozvany, a 32-year veteran of the corporate tax industry.

"And I'm a conservative man, I think the figure is actually much higher," he told the ABC.

"It's very clear to me that the big four accounting firms are the masterminds of international tax avoidance.

"They work with government to deliver what they want for their clients. It's not set in a social context; it's designed to deliver an outcome for their clients."

"The people who are most affected are the most underprivileged in our society, those without a voice. The homeless, foreign aid programs."

Mr Rozvany spent 32 years working in the corporate tax field, for Ernst and Young, Coopers and Lybrand (now PwC) and the defunct Arthur Anderson.

He was head of tax for chemical giant ICI in Australia as well as for the world's largest insurer, Allianz.

Mr Rozvany is Australia's most published author on transfer pricing, a technique that multinational companies are using increasingly to shift profits from high tax to low tax jurisdictions.

While his legal texts explained how to work within the law, Mr Rozvany argues that sham transfer pricing arrangements are now out of control.

"Transfer pricing behaviour clearly is the greatest concern because it's very easy for a transfer pricing expert to dress up a sham transaction as a real commercial transaction," he explained.

"I'm talking about service arrangements, intellectual property transfers, such as patents or use of patents, and perceived transfer of goods, sham loans between related parties, but in reality it's all about providing services at too high a price which then shifts [income] to a lower tax jurisdiction."