The federal attorney-general has refused to be drawn on the case of a former Australian Taxation Office debt collector facing prosecution for allegedly releasing protected information.
Richard Boyle's case came before the South Australian Court of Appeal on Wednesday as he tried to overturn an earlier ruling that he should face a criminal trial.
In civil proceedings in the South Australian District Court, Boyle had previously argued his whistleblower actions were consistent with the federal government's Public Interest Disclosure Act, rendering him immune from prosecution.
But in March Judge Liesl Kudelka dismissed his claim, ruling he was not protected by the act, effectively clearing the way for his criminal trial to proceed.
Boyle is facing more than 20 charges related to the release of protected material after he claimed ATO staff had been instructed to use harsher debt collection tactics on individuals and small businesses, including orders requiring banks to hand over money, sometimes without the permission of the taxpayers.
The case includes allegations he taped private conversations without consent and took photos of taxpayer information.
The Human Rights Law Centre has repeatedly urged the federal government to drop the charges and said Boyle's appeal would determine the scope of legal protections for all Australian whistleblowers.
"It is a vitally important test case with significant implications for truth and transparency in this country," senior lawyer Kieran Pender said.
“Boyle faces the spectre of jail for blowing the whistle on government wrongdoing."
Asked about the case in federal parliament, Attorney-General Mark Dreyfus said his powers to discontinue proceedings were reserved for "very unusual and exceptional circumstances".
"Integrity and the rule of law are central to Australia's criminal justice arrangements," he said.
"Mr Boyle's proceedings remain ongoing ... it would be inappropriate to comment."
Boyle first raised his concerns through internal ATO processes and then made a complaint to the tax ombudsman before taking part in a joint media investigation.
Follow-up reviews found his allegations of aggressive debt recovery practices at the ATO at the time were valid.
A federal parliamentary report also found the ATO had conducted a "superficial" investigation into his public interest disclosure.
