Criminal charges against Richard Boyle, who blew the whistle on aggressive tax collection practices, have been dropped but advocates want the prosecution ended.
The Commonwealth prosecutor on Friday dropped five charges including three counts of attempting to disclose protected information and two counts of attempting to divulge or communicate a tax file number.
But three other charges of attempting to disclose protected information remain.
Tosca Lloyd from the Whistleblower Justice Fund called for all charges to be dropped.
"While it's good news that the prosecutions are not proceeding with five counts against Richard Boyle, the latest development only demonstrates the absurdity of the whole saga," he said.
"Whistleblowers should be protected not prosecuted. This prosecution damages Australia's democracy and today's development is a stark reminder of that."
Boyle was at one stage charged with 24 offences that included allegedly making illegal recordings of conversations and copies of sensitive information before he blew the whistle on unethical debt recovery practices in the Australian Tax Office.
The 49-year-old faced decades behind bars if convicted.
His lawyers had entered negotiations with prosecutors in December, hoping to strike a plea deal and avoid jail time.
In a February social media post, Boyle said he withdrew instructions for his legal team to negotiate a plea deal with the Commonwealth.
He said he "cannot in good conscience" continue negotiations while prosecutors pursued charges in light of some of the evidence heard in court.
A number of the charges Boyle mentioned in the post were the ones dropped on Friday.
Talks continue ahead of the next court hearing set for May after the judge encouraged dialogue between the parties.
A trial is set for November 2025.
