Tax dodging by Australian-based multinationals through 15 of the worst corporate tax havens cost Australia up to $4.8 billion in 2014, 90 per cent of Australia's lost corporate tax, a new report from Oxfam has revealed.

The top three offshore financial centres used by those multinationals operating in Australia were Switzerland, Singapore, and the Netherlands.

On a global basis, Bermuda topped the list as the worst tax haven, with 0 per cent corporate income tax, 0 per cent withholding taxes, evidence of large-scale profit shifting and a lack of transparency.

The Cayman Islands, Ireland, Luxembourg, Hong Kong and the Bahamas were also named in the top 15.

Oxfam's ranking of the top 15 corporate tax havens 1 Bermuda 2 Cayman Islands 3 Netherlands 4 Switzerland 5 Singapore 6 Ireland 7 Luxembourg 8 Curacao 9 Hong Kong 10 Cyprus 11 Bahamas 12 Jersey 13 Barbados 14 Mauritius 15 British Virgin Islands

The report, titled "Tax Battles", argued there is a growing "race to the bottom" on corporate tax rates, with governments around the world continuing to slash, or planning to drop, tax rates.

Oxfam noted the average corporate tax rate across G20 countries was 40 per cent 25 years ago, compared to less than 30 per cent today.

"There is no winner in the race to the bottom on corporate tax," noted Muheed Jamaldeen, senior economist at Oxfam Australia in the report.

"The Australian Government has a responsibility to join efforts to stop this race to the bottom on corporate tax rates, and demand that companies pay their fair share - at home and abroad."

Despite net profits by the world's largest companies tripling in real terms over the last 30 years, from $2 trillion in 1980 to $7.2 trillion by 2013, tax contributions of large corporations are diminishing, the report said.

On top of that, Oxfam said 90 per cent of the world's biggest companies had a presence in at least one tax haven.

Tax havens are firmly entrenched in the global financial system and, according to the Tax Justice Network, account for 50 per cent of all world trade.

"Creating a public list of the world's worst tax havens is a step towards creating disincentives for multinationals to use them," said Mr Jamaldeen.

"It is also about transferring the burden of proof back onto companies to prove that operations in these jurisdictions are genuine."

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Around 62 people own the same wealth as the bottom 3.6 billion people, Oxfam said.

Developing countries lose around $100 billion annually as a result of corporate tax avoidance schemes.

Oxfam said this amount is more than enough to provide an education for all of the 124 million children currently out of school, and to pay for health interventions that could save the lives of 6 million children.

Incentives granted without close scrutiny: Oxfam

Oxfam noted that a failure to agree to a definition of a 'tax haven' has contributed to their legitimisation.

The non-governmental organisation stated that, while almost all countries provide tax incentives, those incentives are granted to multinationals without close parliamentary or public scrutiny.

"As a result, tax incentives are often ineffective and have become associated with abuse and corruption," the report said.

"Tax revenues are needed to fund public goods and services, which contribute to the reduction of poverty and to the development of social and economic infrastructure.

"It is crucial that the Australian Government modifies current legislation so that multinational companies that function in or from Australia report publicly on their incomes, employees, profits earned and taxes paid in every country in which they operate."

The Coalition Government is proposing to cut the company tax rate to 25 per cent for all firms in the next 10 years, and the Federal Treasury predicts the measures could cost the budget more than $48 billion over a decade.

The Government argues cutting company taxes will keep Australia internationally competitive, attract more foreign investment and produce a bigger and more productive economy.

In June, another Oxfam report found the Australian economy loses up to $6 billion in corporate tax revenue annually.