The Human Rights Law Centre will participate in an appeal by former Australian Taxation Office debt collector Richard Boyle, who is seeking to halt his prosecution over allegedly releasing protected information.
Boyle's appeal will be heard in August with the law centre granted leave to appear as amicus curiae or as a friend of the court.
Such leave recognises the organisation may be able to assist on points of law or other issues related to the case.
In civil proceedings in the South Australian District Court, Boyle had previously argued that 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 in October.
He is now seeking to appeal that decision.
Human Rights Law Centre senior lawyer Kieran Pender said Boyle's appeal could determine the strength of protections for all Australian whistleblowers.
"It is a vitally important test case with significant implications for truth and transparency in this country," he said.
In the criminal case, 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.
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.
The civil action to block the prosecution was the first of its kind and was considered instrumental in determining the strength and effectiveness of national whistleblower protections.
In his evidence, Boyle told the court he had been suffering from post-traumatic stress disorder, and alleged he had been psychologically abused after he first tried to use internal processes to bring his issues to light.
