LEIGH SALES, PRESENTER: In the past few years the Australian Tax Office has spent more than $400 million pursuing wealthy tax dodgers. It's led to 3,000 people, including stars like Paul Hogan, being audited and 20 being convicted. And yet the use of offshore tax havens by Australian corporations is still flourishing. As Greg Hoy reports, majority of the top 100 companies on the Australian Stock Exchange use so-called "secrecy jurisdictions" abroad, leading to calls for a new crackdown.

JOHN CHRISTENSEN, FOUNDER, TAX JUSTICE NETWORK: We're allowing very many powerful companies to pay no tax whatsoever and I think it's a disgrace. It's an act of enormous political cowardice that our political leaders around the world haven't paid more attention to this issue.

GREG HOY, REPORTER: This issue is the enduring popularity of tax havens or secrecy jurisdictions, often found on far-flung treasure islands such as the Caymans, Bahamas, British Virgin or Channel Islands, and tiny European principalities and dukedoms like Luxembourg or Liechtenstein. For a fee most tax havens offer extremely low tax rates and high levels of secrecy luring corporate capital seeking refuge from the tax man.

MARK ZIRNSAK, UNITING CHURCH JUSTICE MISSION: Some of it... there is clearly tax evasion going on and that's where people are breaking the law and in other cases there's tax avoidance where people are using loopholes in the law to avoid paying their fair share of tax. Now, that might be legal, but it's completely unethical.

GREG HOY: Of the top 100 companies listed on the ASX, 71 held subsidiaries in financial secrecy jurisdictions last year. These include Telstra, Westfield and News Corporation, to name a few.

JOHN CHRISTENSEN: When you look at Australian companies, you will see that many of them are using tax havens.

GREG HOY: Economist and accountant John Christensen worked for the government of Jersey in the Channel Islands for 11 years.

JOHN CHRISTENSEN: I'm trained as a forensic auditor. What I found was tax evasion and tax avoidance on a mass... a colossal scale.

GREG HOY: So he co-founded the Tax Justice Network.

JOHN CHRISTENSEN: Pinstripe infrastructure - bankers, the lawyers and so on - are engaged in economic war fare. They're engaged in attacking democracy itself.

GREG HOY: 7.30 sought responses from five prominent companies. Telstra, which has many subsidiaries in such places as Jersey, Bermuda, the Cayman Islands and British Virgin Islands, simply didn't respond. Nor did Rupert Murdoch's News Corporation, which has around 150 subsidiaries in similar offshore places. Australia's largest-listed property company, the Goodman Group, which also has subsidiaries in Jersey, the Cayman Islands, Luxembourg and elsewhere, said it "uses subsidiaries in low tax jurisdictions to provide a tax-neutral way for our Australian investors to invest in foreign countries". The Westfield shopping group said: "These structures are common in both the global real estate industry and both the Australian and UK tax authorities are aware of Westfield's organisation."

GRAEME COOPER, TAXATION LAW, SYDNEY UNIVERSITY: I kind of doubt if there's a lot of money offshore, held offshore by big Australian corporates.

GREG HOY: Tax lawyer Graeme Cooper is professor of tax law at Sydney University and a senior consultant to the largest specialist tax advisory law firm in Australia, Greenwoods and Freehills - and he's a staunch critic of the Tax Justice Network and its supporters.

GRAEME COOPER: I don't want to be giving people the impression that Australian corporates don't use tax havens. But they don't leave money sitting in there. The money goes in, the money goes out. So if you ask: why do multinationals use tax havens? The answer is typically for convenience, not for tax.

MARK ZIRSNAK: If companies want to argue that everything they're doing is completely legitimate and have no concerns about it at all, then they should be quite willing to be transparent about exactly what each of those subsidiaries are for.

GREG HOY: Dr Mark Zirnsak is director of the justice mission of the Uniting Church of Australia - one of those urging government to clamp down on rampant transfer pricing. Transfer pricing is when a company's subsidiary in a tax haven charges often exorbitant prices to its parent company back home, with the effect of greatly reducing its parent's tax bill.

MARK ZIRNSAK: We're talking very large sums of money and therefore very large amounts of tax revenue that countries and the rest of society and communities miss out on, and this has particularly a devastating impact on developing countries.

GREG HOY: NGOs cite the example of global brewing giant SAB Miller, which recently bought out Australia's Fosters Brewing Group and has extensive brewing interests in African nations like Ghana.

ARCHIE LAW, CHIEF EXECUTIVE, ACTIONAID AUSTRALIA: We started working with the assistance of a former senior tax investigator. And that investigation led us to tax havens in the Netherlands, in Switzerland, in Mauritius - where all the profits that are being made in Ghana have been siphoned off into tax haves to minimise SAB Miller's taxation bill.

GREG HOY: SAB Miller sent us a previous statement rejecting AusAid's allegations suggesting it paid significant tax in countries like Ghana, and honoured the OECD principles on transfer pricing - principles that AusAid would like to see reformed.

ARCHIE LAW: SAD Miller have been very defensive, the company is paying no tax, next to no tax in a country like Ghana. We have never accused SAB Miller of doing anything illegal. What we are saying is that what they are doing is immoral and it comes from an ethically bankrupt organisation to be following this course of action.

GREG HOY: Australia is trying to beef up its transfer pricing rules, and is busy signing information exchange agreements with tax havens. The problem is, evidence of suspected wrong doing must first be produced.

JOHN CHRISTENSEN: We need to move to automatic information exchange as the global standard. We're trying to push the Australian Government to make this the global standard they push when they become President of the G20 in 2014. That is the best way of tackling tax evasion.

GREG HOY: So will Australia answer the call to wage war on the treasure islands of tax when it takes over presidency of the G20 group of leading economies?

DAVID BRADBURY, ASSISTANT TREASURER: We will continue to work in all international fora that we participate, and in all capacities, to advocate the case for greater transparency. But in the end, you do need to bring other nations to the table to reach agreement on the terms under which you enter into your information exchange agreement.

GREG HOY: So don't, it seems, hold your breath. Expect strong resistance to change from tax havens themselves, and their many great admirers.