Australia's defence minister won a defamation lawsuit on Wednesday against a refugee advocate who described him as a "rape apologist" in a tweet, a small advance in the conservative government's effort to curb damaging commentary on social media.

Peter Dutton, an outspoken cabinet minister, experienced "hurt and distress" when shown the Feb. 25 Twitter post by a staff member, although his public profile would have meant most people viewed it as opinion rather than a fact, a federal court judge ruled.

The lawmaker was awarded A$35,000 ($25,000) in damages, a fraction of the maximum amount possible, after the judge found that Dutton had been defamed but his day-to-day life was not impacted by the now-deleted tweet.

The ruling marks another milestone in a campaign by the government to rein in what it has called a "coward's palace" of vindictive shared on social media. Earlier this year, former attorney general Christian Porter settled a defamation action against the Australian Broadcasting Corp over Twitter posts about a historic rape allegation which he denied.

Dutton's lawsuit against activist Shane Bazzi was over a midnight tweet on a day when the politician, who was then immigration minister, defended in media appearances his handling of a complaint about sexual assault inside parliament house.

Bazzi tweeted a link to a 2019 article in which Dutton suggested some refugees claiming to be rape victims were "trying it on" to be allowed into Australia, coupled with the sentence "Peter Dutton is a rape apologist".

Dutton was accustomed to the "rough-and-tumble of politics" but "deeply offended by the tweet", noting that Bazzi's account had a blue tick, indicating that he was a verified user, said the judge, Richard White in his published ruling.

The "description of Mr Dutton as a person who excuses rape was no doubt a serious defamation" but "he did not claim to have suffered more serious consequences by reason of the publication of the Tweet or even that his hurt and distress had continued to the date of trial", the judge added.

A representative for Dutton was not immediately available for comment. Bazzi said in a tweet that was he "very disappointed with the outcome" and would consider his options.