The office of employment minister Michaelia Cash has refused to confirm the existence, or release, communications between Cash, her staff, and other key players in the scandal over Cash's office leaking information about the police raid on Australian Workers' Union (AWU) offices to the media.
The AWU Sydney and Melbourne offices were raided by the Australian Federal Police (AFP) on the behalf of the Registered Organisations Commission (ROC) in late October in relation to donations made by the union over a decade ago when it was led by current Labor leader Bill Shorten.
Media arrived at the offices before the raids took place, and BuzzFeed News revealed that media outlets had been tipped off about the raids by Cash's office.
During the course of the day at Senate Estimates before the story was published, Cash denied five times that she or her staff members had informed the media of the raid.
"Quite frankly I am offended on behalf of my staff as to those allegations," Cash said at the time. "They are very serious allegations."
After the story was published, however, Cash changed her tune. She said that a senior advisor, David De Garis, had admitted to tipping off the media about the raids and had subsequently resigned. Cash repeatedly denied that she knew of the leak and said she did not authorise the leak to the media.
The following day, the government tabled an email from the AFP stating it was investigating the leak, and as a result the government subsequently refused to answer all questions.
Now the government is using that same investigation to prevent releasing any communications between specific staffers in Cash's office, Cash herself, and staff at the Fair Work Commission and ROC, related to the AWU raids and the Senate Estimates hearing.
BuzzFeed News filed a freedom of information request for these communications last month, and in a response emailed at 11:10pm on the date the FOI response was due to be received, Cash's chief of staff, Ben Davies, refused the request to hand over communications, citing the AFP investigation.
"The Australian Federal Police has commenced investigations into the alleged unauthorised disclosure of information concerning the execution of search warrants obtained by the Registered Organisations Commission," Davies said.
"Any disclosure of information that may be relevant to this investigation, including the acknowledgement of the existence or otherwise of any documents within the subject matter of the request, could prejudice the law enforcement investigation currently carried out by the AFP by inhibiting the provision of information by potential witnesses; influencing lines of inquiry by police or the evidence of witnesses; or disclosing avenues of inquiry."
It has been speculated that the tip-off to De Garis may have come from staff members in the Fair Work Commission or the ROC, as they would have been aware of the raids in advance. Cash has only said that the tip off came from "a media source".
Labor senator Murray Watt — who is on the estimates committee that probed Cash on the leak — said in a press conference on Tuesday that Cash was "desperate to cover up her office and potentially her own involvement in this scandal".
"I'm extremely worried that she is ignoring legal requests from the media to produce documents," he said.
"That's what we have a freedom of information act for, is to allow people to find out what's going on behind the scenes in government. So she seems so determined to cover up her own involvement, it only makes you actually more suspicious of her own personal involvement in the affair."
BuzzFeed News plans to appeal the decision.
Cash is due to front a committee on the matter again on Friday.
It has been 33 days since Cash fronted the employment committee to answer questions about the matter. At the last meeting, she sent attorney-general George Brandis in her place.
Labor and Greens senators have offered to make themselves available on any Saturday or Sunday from November 3 to December 6 to resume the committee, but the minister has refused.