The report, The Hidden Billions – How tax havens impact lives at home and abroad, says multinationals companies operating in Australia use low-tax or no-tax nations to avoid paying tax locally.

It says Australian-based multinationals use "tax havens" that cost Australia $6 billion in lost tax revenue annually, and developing countries an estimated $US2.3 billion ($2.8 billion) every year.

The report, being launched on Thursday, comes as an online poll shows 90 per cent of more than 1000 Australians surveyed think the government should do more to stop multinational corporations avoiding paying tax.

"Australians and poor people in our region are missing out on because Australian-based multinational companies aren't paying their fair share of tax like the rest of us," Oxfam Australia chief executive Dr Helen Szoke said.

Tax loss figures 'conservative'

Oxfam's figures do not state how many multinationals dodge tax, it simply estimates that nearly one in every $5 of overseas investment in Australia came from a 'tax haven' in 2014.

"Our research relies on IMF data, which shows the flow of money from Australian-based multinationals," Dr Szoke said.

"Unfortunately, there is no way to find out which individual companies are dodging tax, as they're not required to publish their tax affairs on a country-by-country basis."

Oxfam has called for a publicly available country-by-country reporting of financial information, so that the public does not have to rely on estimates or tax leaks such as the Panama Papers to know the true extent of tax dodging.​

It says the estimates contained in the report are "inherently conservative" since they are based on Australian-based multinational corporations directly investing in 20 low-tax or no-tax jurisdictions.

"There are many other tax tricks available to multinational corporations to reduce their tax bills in the countries in which they operate". 

No universal definition of a tax haven

While there is still no universal definition of a tax haven, Oxfam's report identifies what it believes are 20 "tax havens" including Singapore, Hong Kong, Ireland, Netherlands, Malta, Malaysia, Bermuda, Fiji, Cayman Islands, Luxembourg, Belgium, Austria, Samoa, Costa Rica, Virgin Islands, Panama, Macao, Cyprus, Barbados and Jordan.

It says investment in these tax havens increased by 40 per cent (or $US22.7 billion) between 2009 and 2014. "We estimate that $US7.7 billion in profits were hidden in tax havens by Australian-based multinationals in 2014."

Its figures do not distinguish between legal and illegal tax strategies. "Arguably they are both immoral and inherently unfair," the report says, although it notes Ireland has recently moved to counteract tax avoidance by phasing out of the "Double-Irish" structures.

But the Organisation for Economic Cooperation and Development (OECD), which has vowed to end tax havens via its Base Erosion and Profit Shifting (BEPS) plan, has said that tax competition - that is, having a low tax rate - is acceptable, but no-tax nations are not.

The OECD's head of tax Pascal Saint Amans has said Singapore does not allow "sham businesses" to set up, but has questioned whether the right amount of money was being located there.

Developing countries lose out

Globally, Oxfam estimates about $US638 billion in profits was shifted out of developing countries by multinational corporations operating all around the world.

This resulted in around $US172 billion of tax revenue being ripped out of 110 developing countries, it says.

"Forty-six of the developing countries that received the largest amount of investment by Australian-based multinationals, had an estimated $US2.3 billion in tax revenue ripped from them," the report says.

It estimates $US33 million is being torn from programs that would otherwise have targeted gender inequality and help improve conditions for women in developing countries.

"The world's poorest people, and women in particular, bear the brunt of harmful tax dodging – they are the human face of tax dodging," the report says.

Rich get richer

It says this is happening as the wealth of the richest people in the world has been steadily increasing.

In 2015, the richest 62 individuals in the world owned more wealth than the poorest 50 per cent of people combined.

Oxfam says the Australian government needs to "act swiftly" and match its rhetoric with stronger laws to stop tax dodging.

Tax Commissioner Chris Jordan has repeatedly said the Australian Taxation Office is not soft on tax dodgers.

But Oxfam wants the government to legislate further disincentives beyond the Diverted Profits Tax. The Coalition's laws, introduced in Joe Hockey's final days as treasurer, impose strict penalties on companies that have substantial economic activity in Australia but that count their profits offshore.

"The solutions proposed so far — while a step in the right direction — do not go far enough," the report says.

Call to name and shame tax dodgers 

It calls on the government to modify current tax transparency legislation so that multinational companies with an income of A$250 million or more have to publicly report on their incomes employees, profits earned, and taxes paid, in every country in which they operate.

"This will make the use of tax havens more transparent, and make it harder for large corporations to continue to shift profits out of the poorest nations," the report says.

Oxfam also calls on the government to not abandon its commitment to establish a public registry of the ultimate owners of companies, foundations and trusts.

It says such a register would deter Australians from acting as the "front people" for shell companies in tax havens.

At the same time, it says the government should also consult with the International Monetary Fund (IMF) and the OECD to develop a list of tax havens.

It should also transfer the burden of proof to companies, requiring them to demonstrate a legitimate reason for investing in a tax haven.