A court is expected to hear that a refugee advocate honestly believed that Defence Minister Peter Dutton condoned or excused rape when he tweeted that Mr Dutton was a “rape apologist”.

The Queensland MP is suing Shane Bazzi over the now-deleted tweet.

Mr Dutton said on the opening day of the trial on Wednesday that he was “deeply offended” by Mr Bazzi’s tweet of February 25.

“It went against who I am, my beliefs … I thought it was hurtful,” the frontbencher told the Federal Court.

After first arguing the tweet did not actually convey that Mr Dutton condoned or excused rape, Mr Bazzi’s barrister, Richard Potter SC, is due on Thursday to submit that his client is protected by the defences of honest opinion or fair comment.

Peter Dutton is suing over the ‘rape apologist’ tweet. Photo: AAP

He described the honest opinion defence on Wednesday as “a fundamental protection in our society” and “a bulwark of freedom of speech”.

An honest opinion can be “extreme or offensive” but still permissible if it’s based on proper material, Mr Potter said.

The written defence includes comments by Mr Dutton that some refugees who claim they’ve been raped are “trying it on”.

It also refers to Mr Dutton’s public response to an allegation made by former Coalition staffer Brittany Higgins, who says a colleague sexually assaulted her in parliament house.

Mr Dutton has said a federal police briefing on the matter did not provide him with the “she said, he said details”.

Ms Higgins appeared to watch the proceedings online on Wednesday.

She tweeted on Wednesday afternoon that she found Mr Dutton’s claim that he was offended by Mr Bazzi’s tweet “baffling”.

She said she had been “offended plenty” by Mr Dutton’s response to her allegation and described the case as “a shocking indictment on freedom of speech”.

It’s the first time in a 20-year political career that Mr Dutton has sued for defamation, despite regularly being the subject of “unpleasant observations”, the minister’s lawyer, Nick Ferrett QC, told the court on Wednesday.

Justice Richard White on Wednesday cautioned the parties that it was not a large defamation case by the Federal Court’s standards, and asked them to assure him they’d tried to settle it.

“It does seem to me that this should be a matter capable of resolution. There are risks on both sides,” the judge observed.

-AAP