The One Nation leader is battling a 2024 Federal Court finding that she racially vilified Greens senator Mehreen Faruqi in a tweet posted shortly after the death of Queen Elizabeth II.
Senator Hanson's tweet included telling Senator Faruqi to "piss off back to Pakistan".
Her barrister told an appeals court in November that her remarks might not have been pleasant but they did not intimidate people of colour.
On Monday afternoon, the Full Court of the Federal Court will decide if the online attack did breach racial discrimination law.
The 72-year-old will be hopeful of a positive result after increased scrutiny on her overseas activities coincided with a drop in recent polls.
She has come under fire since returning from a European trip, where she was seen holidaying in Italy with billionaire donor Gina Rinehart.
Senator Hanson also met with anti-immigration activist and convicted criminal Tommy Robinson and told a conservative conference Australia had been flooded with migrants.
A Roy Morgan poll published on Tuesday showed her anti-immigration party's primary vote dipped more than five percentage points to 22.5 per cent in the space of a week.
It comes four years after her retort to a political opponent's tweet landed her in hot water.
The day of the Queen's death, Senator Faruqi took to Twitter, now known as X, to offer condolences to those who knew the monarch.
But she added she could not mourn the passing of the leader of a "racist empire built on stolen lives, land and wealth of colonised peoples".
In a response, Senator Hanson said she was appalled and disgusted by the comments.
"When you immigrated to Australia you took every advantage of this country," she wrote.
"It's clear you're not happy, so pack your bags and piss off back to Pakistan."
Senator Hanson's barrister Sue Chrysanthou admitted the remarks were not fit for an afternoon tea or the courtroom.
But she argued the court's finding that Senator Hanson's remarks actually intimidated Australian migrants of colour was extreme.
Senators Faruqi and Hanson have also clashed in some of the right-winger's more eye-catching stunts on the floor of the Senate.
The Greens senator accused Senator Hanson of blatant racism and Islamophobia when she wore a burqa into parliament, just six days after the appeal hearing in November.
It was the second time the senator had pulled the burqa stunt.
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