Federal Attorney-general Nicola Roxon says several Queensland Liberal National Party identities, including former Howard government minister Mal Brough, must answer questions over an alleged political vendetta against federal speaker Peter Slipper.
Mr Slipper's former adviser James Ashby has accused his previous boss of sexual harassment in claims that have had widespread media coverage.
Now, the Commonwealth has applied to the Federal Court to find Mr Ashby'S claims are an abuse of process filed for an ulterior purpose, rather than a genuine workplace complaint.
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The Federal Court has subpoenaed several people connected to the case, including Mr Brough, News Limited journalist Steve Lewis and another of Mr Slipper's staff, Karen Doane.
Federal Attorney-General Nicola Roxon said the Commonwealth would use a number of text messages between those subpoenaed to support its case that the claims made against Mr Slipper were designed to advance his political opponents.
"It will be clearly shown, and this will be argued in the court, that there were in fact clear intention(s) to harm Mr Slipper and bring his reputation into disrepute and to assist his political opponents and that was the purpose of the bringing of this claim," she told reporters in Melbourne on Friday.
"There are a large number of Queensland Liberal National Party identities that are clearly going to be brought up within the course of these hearings and Mr Brough is one of those."
Mr Slipper defected from the Liberal National Party last year to become Speaker.
Mr Brough confirmed on Thursday he will seek preselection in Mr Slipper's Sunshine Coast seat of Fisher.
The attorney-general said although she would not yet use the word conspiracy, there were many questions to be answered.
"Who knew what and when, at whose urging was this action taken?
"Is it internal Liberal National Party shenanigans, there is active involvement of at least one person from the media - those issues will all get aired and tested in the hearing."
