The Australian Taxation Office may use information from data leaks to go after dodgy taxpayers.
Mining company Glencore had launched a legal case against the ATO in order to argue that information from the massive Panama Papers leak should not be used.
But on Wednesday, the High Court ruled in the tax office's favour in Glencore International vs Commissioner of Taxation.
ATO second commissioner Jeremy Hirschhorn said it would have been "perverse" if the tax office could not use information already in the public domain.
"Today’s decision is not just a win for the ATO – it’s a win for the Australian community who rightly expect the ATO to use all information available to ensure large corporations and those who seek to hide money overseas are paying the right amount of tax," he said.
"Once we have information we can’t just ignore it – we are obliged to use all relevant information we have."
The court ruled that all the data was fair game, even if they were leaked from a law firm, and even if it's an overseas law firm. Glencore had used lawyers in Bermuda.
Hirschhorn said the decision is critical in stopping tax rorters.
"The broader ramifications of this decision beyond Glencore are that the days of being able to hide money overseas are rapidly coming to an end – not only are foreign banks providing the ATO with details of Australians with offshore money, but taxpayers are only one data leak away from their entire affairs being exposed."
The ruling has raised the possibility that Australian data could become more attractive for hackers around the world.
Clayton Utz partner Amber Agustin told the ABC that the case had left other legal areas like unjustified invasion of privacy or breach of confidence under a cloud.
"And the law, in this area, may be in need of expansion given the frequency of large scale data hacks," she said.
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