The Greens deputy leader will be allowed to show evidence of an alleged decades-long tendency by Pauline Hanson to make hateful statements about race or colour in an upcoming hearing on alleged racial hate speech.
Mehreen Faruqi has filed a Federal Court lawsuit over a "hateful" September 2022 tweet by Senator Hanson, who wrote that she should "Pack (her) bags and piss off back to Pakistan".
Senator Hanson's tweet came in response to the Greens deputy leader's comments following the death of Queen Elizabeth II.
Senator Faruqi wrote she could not mourn the passing of the leader of a "racist empire built on stolen lives, land and wealth of colonised peoples".
At a hearing in February, the One Nation leader launched a wide-ranging attack on the admissibility of evidence proposed by Senator Faruqi.
This included lay affidavits by people who saw and were impacted by Senator Hanson's tweet and expert reports about racism and the phrase "go back to where you came from".
The One Nation head also targeted proposed evidence aimed at showing she had a tendency to make comments over three decades regarding race, colour and ethnicity that were consistent with holding white supremacist views.
On Tuesday, Justice Angus Stewart rejected the majority of Senator Hanson's claims the evidence could not be relied on in the upcoming five-day hearing, scheduled to begin on April 29.
Submissions that expert reports on the effects of racism should be tossed because section 18C of the Racial Discrimination Act did not specifically reference the word "racism" were rejected.
"The submission that the consideration by the witnesses of the effects of 'racism' on individuals and society is inadmissible because the word 'racism' is not found in section 18C is bewildering," the judge wrote.
The section was aimed at combating racist behaviour in Australia, he noted.
Evidence relying on things Senator Hanson said in Parliament such as her "It's OK to be White" motion in 2017 was ruled out by Justice Stewart who found it infringed parliamentary privilege, or the right of politicians to speak while inside parliament free from ramifications.
However, other evidence aimed at proving Senator Hanson had specific tendencies was allowed.
"(If) she has a tendency to make public statements because of the race, colour or national or ethnic origin of a person or a group of people or to engage in commentary consistent with holding white supremacist views, it is more likely that she published the tweet in question 'because of' the asserted reason," the judge wrote.
Senator Faruqi's solicitor Michael Bradley called the case "groundbreaking".
"This case is groundbreaking, because it examines the way that racist hate speech is developed over time, the hidden or coded meanings it takes on and the messages it communicates to both its victims and perpetrators," he said.
Because of Justice Stewart's ruling, the court could conduct a wide-ranging inquiry supported by the appropriate evidence, Mr Bradley said.
Senator Hanson declined to comment on the judgment.
