In documents made public today, Mr Ashby says officials in John Howard's government knew as far back as 2003 that Mr Slipper - who was then a Liberal MP - "had formed a relationship of a sexual nature with a younger male member of staff" employed in his office.
The documents allege that Tony Nutt, a senior adviser to then-prime minister Mr Howard, was told of the allegations "in or around mid-2003".
It says a former Slipper staffer, Megan Hobson, had seen a video in which Mr Slipper "was observed to":
"...enter the bedroom of a junior staff member through the window";
"... lie on a bed with the junior male staff member in shorts and T-shirt and hug the junior male staff member in an intimate fashion";
"... urinate out of the window of the room."
The documents allege that Mr Nutt then told Ms Hobson to "forget all about it".
"The Commonwealth thereafter failed to take reasonable and effective steps to prevent the Second Respondent [Mr Slipper] from utilising his office to foster sexual relationships with young male staff members," the claim alleges.
The court documents also said the staffer in question showed Ms Hobson "scabs on his knuckles where he said he had recently hit a brick wall whilst defending himself against an attack by Peter Slipper during a parliamentary trip to Adelaide".