High-profile MPs to be witnesses in Latham defamation

Greens senator Sarah Hanson-Young will give evidence about the Sydney MP's character and state of mind following Mr Latham's tweet, which Mr Greenwich claims subjected him to a "torrent" of homophobic and other abuse.

The Speaker of the NSW Legislative Assembly and fellow independent MP Greg Piper will also appear as a witness in support of Mr Greenwich.

Barrister Matthew Collins KC, representing Mr Greenwich, told a brief Federal Court hearing on Wednesday that a five-day trial could be set for later in the month.

Also appearing as witnesses at the trial will be Mr Greenwich's husband, Victor Hoeld, and two staff members from his electorate office, Anne McCall and Alexander Graham.

Mr Greenwich is suing Mr Latham, a former federal Labor opposition leader, over the graphic tweet describing explicit sexual acts between men, which came in response to an earlier tweet in which he called Mr Latham a "disgusting human being".

The lawsuit targets both Mr Latham's tweet and statements made during an interview with the Daily Telegraph in which the then-One Nation state leader discussed Mr Greenwich giving speeches about sexuality to students in schools.

"Mr Latham linked that in a disgraceful manner to conduct which was in fact understood ... to be in the nature of grooming," Dr Collins told an earlier hearing.

Mr Latham has denied that he defamed Mr Greenwich and is defending the lawsuit.

Barrister Barry Dean earlier said Mr Latham was fighting the case by arguing his tweet was a reasonable response to Mr Greenwich's initial attack, adding that the comments were the conservative MP's honest opinion at the time.

He also argues there had been no serious harm done to Mr Greenwich and that his reputation remained the same regardless of what was said.

Dr Collins has called for the trial to commence with the parties' opening statements on May 22.

Australian Associated Press