“To allow these proceedings to remain in the court would bring the administration of justice into disrepute among right-thinking people and would be manifestly unfair to Mr Slipper,” explained Justice Steven Rares.
Slipper left his post as speaker in April, after he was accused of harassment by James Ashby, who said he sent text messages and made sexual advances, including urging him to shower with the door open at an apartment in Canberra.
Ashby said he was “extremely disappointed” with the ruling and that he intended to launch an appeal.
Ashby has been ordered to pay the legal costs involved in the case.
“I feel vindicated by today’s judgment,” said Slipper.
“The past eight months have been extremely traumatic for my wife, family and me.
“I thank my wife, family, staff and friends for their support during this extraordinarily difficult time.”