Mark Latham will defend a defamation claim by arguing his wrong assumption that a Sydney university student had plotted to kill senior federal MPs and blow up the Sydney Opera House was his "honest opinion" and caused little harm.
Mohamed Kamer Nilar Nizamdeen is suing the One Nation politician over two since-deleted tweets posted the day the University of NSW PhD student was charged with a terror-related offence.
Police initially accused Mr Nizamdeen of authoring a notebook containing threats to kill senior politicians and blow up a number of sites.
But the charge was later dropped and his colleague, Arsalan Khawaja, was accused of trying to frame Mr Nizamdeen.
Mr Latham's lawyer, Tean Kerr, told the Federal Court in Sydney on Wednesday the matter would be defended on the basis the tweets were "honest opinion" and the harm caused was trivial.
Mr Kerr said the tweets on August 31 were concurrent with a series of news reports mentioning the police allegations made against Mr Nizamdeen and statements made by Senator Fraser Anning.
Mr Latham - who's to be elected to the NSW upper house within days - deleted the tweets in late March after the defamation claim was made.
Mr Kerr said that had mitigated the damage.
Mr Latham's first tweet mentioned Mr Nizamdeen by name and said he "was plotting to kill senior federal MPs and blow up Sydney Opera House and police/train stations".
A second, posted 20 minutes later, referred to a UNSW tweet about where to start on the university's open day.
"Try avoiding Mohamed Kamer Nilan Nizamdeen and any of his mates!!!" Mr Latham posted.
Shortly after the defamation claim was filed with the court and Latham's election to the NSW parliament was all but confirmed, the tweets were deleted.
"At the time I tweeted in relation to this story but have now been advised that police have dropped the charges against Mohamed Nizamdeen," he tweeted on March 24.
"It seems he was falsely arrested, a terrible experience to go through. I have deleted my comments accordingly and urge the ABC to do the same."
In a statement of claim lodged with the court, Mr Nizamdeen's lawyer argues his client had "suffered hurt and embarrassment and has suffered and will continue to suffer loss and damage".
"The applicant has been brought into hatred, ridicule and contempt, and has been gravely injured in his character and reputation," the document states.
