Mining billionaire Clive Palmer, who has savaged the federal government's mining tax, reportedly did not have to pay tax in his main private company last year.
Fairfax says accounts lodged with the corporate regulator for Mineralogy and its subsidiaries reported losses for the past three financial years.
The profit-and-loss statement shows no tax was payable in 2010-11, nor in 2009-10 or in 2008-09.
Mineralogy owns rights to huge magnetite iron ore deposits in the Pilbara and thermal coal deposits in Queensland's Galilee Basin, but its mines are not yet in production and generating income, Fairfax reports.
Other parts of Mr Palmer's business empire, including Queensland Nickel and various property interests, are held outside Mineralogy.
Meanwhile, Opposition treasury spokesman Joe Hockey has admitted meeting with Mr Palmer, a backer of Queensland's new Liberal National Party government.
News of the meeting has sparked fresh Labor attacks about the Coalition for "kneeling at the feet of billionaires".
Mr Hockey held one-on-one talks with Mr Palmer over the Easter long weekend while visiting Queensland's Sunshine Coast for work and a family holiday, News Ltd reports.
A spokesman for Mr Hockey confirmed the meeting went ahead, but would not say what was discussed or who initiated it.
Assistant Treasurer David Bradbury said Mr Hockey had shown he was happy to "kneel at the feet of billionaires rather than stand up for families and small businesses".
"Mr Hockey needs to explain what he discussed with Mr Palmer, and what promises he made Mr Palmer about Liberal policy," he told News Ltd.
Mr Palmer was unavailable to comment.
A later statement, issued on behalf of Mineralogy, said: "Mineralogy is a private company and as a matter of policy we do not comment on our accounts.
"Clive Palmer is the owner and chairman of Mineralogy and has a vast portfolio of business interests including numerous resource companies such as Queensland Nickel, the Coolum Golf and Spa resort on the Sunshine Coast and golf courses on the Gold Coast.
"Mineralogy lodges its accounts with ASIC and follows all regulatory procedures."