The Commonwealth has racked up more than $7.6 million in legal fees pursuing whistleblowers, with the bulk of that bill relating to a now-dumped prosecution.
Officials from the Attorney-General's Department revealed the cost under questioning from New South Wales Greens senator David Shoebridge, who labelled it as a "lavish use of taxpayer funds".
In July last year, Federal Attorney-General Mark Dreyfus ordered prosecutors to drop the case against Canberra lawyer Bernard Collaery.
Mr Collaery had been charged with helping his client, an ex-spy known by the pseudonym "Witness K" with revealing classified details of a secret mission in Timor Leste.
The Attorney-General's Department confirmed that by the end of January, the case against Mr Collaery and Witness K had cost the Commonwealth $5,510,829.
Senator Shoebridge also sought details of prosecutions against David McBride and Richard Boyle.
Mr McBride is being prosecuted for allegedly leaking top-secret defence information to the ABC, while Mr Boyle is before the courts after lifting the lid on unethical debt recovery practices within the Australian Taxation Office.
Officials revealed the cost of the McBride prosecution had reached $1,875,348, while Mr Boyle's case had reached $233,171.
The Commonwealth's spending in Mr McBride's case was higher, according to Attorney-General's Department officials, because of the extra work needed to protect national security information.
Senator Shoebridge described it as using taxpayer funds for "monstering whistleblowers".
"Is there some point at which … your department reviews the lavish use of public money to jail a whistleblower," he asked.
"I'm not sure I would agree with your characterisation of lavish, it's a significant amount of money," Attorney-General Department Secretary Katherine Jones responded.
The Department's deputy secretary, Sarah Chidgey, noted it was up to the Commonwealth Director of Public Prosecutions, as an independent agency, to decide whether to continue pursuing the two men.
"They continue over time to have regard to the prosecution policy of the Commonwealth, and whether it continues to be satisfied — and that includes consideration of the public interest," Ms Chidgey said.
The federal government has been criticised for pursuing Mr McBride and Mr Boyle by whistleblowing advocates, particularly as it reviews Commonwealth whistleblowing protections.
