Australian Taxation Office (ATO) whistleblower Richard Boyle has lost his appeal to secure immunity from prosecution under protection laws in South Australia's Supreme Court.

Mr Boyle, a former ATO debt collector, is accused of 24 offences, including recording and disclosing protected information.

In March last year, South Australian District Court Judge Liesl Kudelka ruled that Mr Boyle was not immune from prosecution under whistleblower protections.

His appeal was unanimously dismissed by Justices David Lovell, Samuel Doyle and Sophie David on Wednesday.

An interim suppression order on the reasons for the judgement has been imposed.

The matter will likely now go back to the District Court where Mr Boyle is expected to face trial in September. 

If convicted, Mr Boyle could face up to 46 years in prison.

"There's some possibility at the end of the trial that this may be appealed to the High Court," Former senator Rex Patrick said outside of court.

"Of course, that could also happen now — obviously, that's a matter for Richard's legal team to consider."

In a statement, a spokesperson for the Attorney-General Mark Dreyfus said the government was "committed to delivering strong, effective and accessible protections for whistleblowers".

"Given the matter is before the courts, it is not appropriate to comment on this case," the spokesperson said.

"In June last year, the Parliament passed priority amendments to the Public Interest Disclosure Act which ensured immediate improvements to the public sector whistleblower scheme were in place in time for the commencement of the National Anti-Corruption Commission."