Labor senator Sam Dastyari has accused oil and gas multinational Chevron of being the "biggest tax dodger" in Australia.
Chevron Australia managing director Roy Krzywosinski has denied any wrongdoing when it comes to its tax arrangements, and says its contribution to tax revenues will amount to $350 billion once the Gorgon LNG project is up and running.
"It will buy a lot of hospitals, it will purchase a lot of schools ... there is a lot in it for Australia," he told a Senate hearing into corporate tax avoidance in Sydney.
Mr Krzywosinski said the project, which employs 19,000 workers in Western Australia, is in the investment stage and that "not one dollar of revenue has been raised" so far.
But Senator Dastyari described Chevron's evidence as "just extraordinary" and its tax structure involving internal loans as nothing but a "rort".
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"Frankly, we have spent a year trying to find Australia's biggest tax dodger and we have found them, it's Chevron," Senator Dastyari told reporters outside the hearing.
Greens leader Senator Richard Di Natale was equally unimpressed.
"We are having a debate right now about the GST at the same time as companies as profitable as Chevron are not paying their fair share of tax," he said.
Tax Commissioner Chris Jordan said a recent federal court vote was in favour of the ATO challenging the complex loan arrangements of Chevron and its multinational affiliates.
"This decision has the potential for wide-reaching effects," Mr Jordan told the hearing.
Uber and AirBnB also addressed the hearing, insisting they pay their share of tax in Australia - but were unable to share any of their tax details.
"You came to a Senate corporate tax inquiry and didn't work out how much tax you paid last year?" a dumbfounded Senator Dastyari asked.
While Uber has around 15,000 drivers on the road in Australia, its director of public policy Brad Kitschke argued it was only a technology platform and should not be compared to the taxi industry.
Uber Australia does not generate revenue - it is earned by the parent company based in the Netherlands, which repatriates 75 per cent to pay the drivers.
The ATO is pursuing Uber for its drivers to pay GST.
Mr Jordan said being innovative didn't mean "you don't meet your tax obligations".
AirBnB follows a similar model, with the revenue being generated by its Ireland-based parent company.
Both the Netherlands and Ireland are low-tax regimes, but neither company said this was the reason for the location of their respective headquarters.
"The number one reason we're located there is because of access to great talent," AirBnB country manager Sam McDonagh said, drawing laughter from senators.
Uber said the move to the Netherlands "was because it had a highly skilled workforce".
Meanwhile, oil giant BP says it supports a move to force multinationals operating in Australia to publish tax information, but with some conditions, including how they are presented.
