''If the broader population sees that we make sure that the rich - who can really afford to pay taxes - pay, then it's fairer for them and they are more willing to pay their taxes too,'' he said. Mr Cranston said the agency typically recovered $10 for every $1 spent - a return that has led to the program's expansion through regular funding increases. ''That gives you the scale of our efforts,'' he said. ''It's not just for the return on investment but the community's expectation we will deal with wealthy people.'' The ATO runs two dedicated compliance programs for the wealthy, which together employ 500 staff and use sophisticated data-matching systems to assess tax and financial records and determine who will be formally audited. The ''highly wealthy'' program, which monitors 2600 individuals with assets worth more than $30 million, collected nearly $300 million in unpaid taxes and penalties in 2013. More than $2.8 billion has been collected since the program started in 1996, and its success has resulted in funding boosts in 2006, 2008 and 2013.

A further $140 million was recouped last year from a second program that monitors the 70,000 people in Australia with assets worth more than $5 million. The ATO has declined to discuss individual cases for privacy reasons, but Fairfax Media believes that while dozens of breaches have been settled quietly through payment or negotiations, many others have led to collection actions through the legal system. Court records show that a 2013 audit of the former tyre king Bob Jane found the entrepreneur - once worth an estimated $50 million - had allegedly underpayed his tax obligations as far back as the mid-1990s. He has been slugged with a $1.08 million bill. Mr Buckley was sued by the Tax Office for $11.5 million in October after allegedly underpaying or failing to lodge returns since 2003. Mr Buckley, founder of the Ultra Tune automotive chain, is disputing the debt, which includes $6.29 million in interest charges and penalties alone. The ATO tried, and failed, to garnish the $1.8 million in prizemoney he received for winning last year's Cox Plate. Mr Buckley did not respond to a request for comment. But a solicitor who represents wealthy Australians in tax disputes claims that some staff at the Tax Office have an ''aggressive'' attitude towards the rich that is often ''grossly unfair''.

''They go in with preconceived ideas about the wealthy that they must be doing something wrong,'' the source said. ''The ATO is also empowered to issue a tax assessment, demand payment and go after your assets, notwithstanding the fact that there might be a legitimate objection.'' The flamboyant entrepreneur Mr Edelsten, who was bankrupted by the ATO in the 1980s, once described the agency as ''the Gestapo in Australia's modern society''. The 70-year-old, who recently filed for bankruptcy in the United States, received a $5 million bill in May after allegedly underpaying his tax obligations by nearly 50 per cent in 2011. ''We have found in recent times that the ATO offices have been courteous and of assistance,'' Mr Edelsten's solicitor said. Late last year, the well-known art dealer Mr Ioannou was sued in the Victorian Supreme Court over a $3.3 million tax bill. He could not be reached for comment. Tax experts say the looming blow-out in the federal deficit is said to be one reason the government has increased its focus on recouping unpaid taxes.

But the blitz also comes as the ATO plans to lay off 900 employees and cut costs by allowing big companies greater scope to self-report tax obligations without active oversight. ■cvedelago@fairfaxmedia.com.au