Senator Pauline Hanson is being sued for racial discrimination in the Federal Court by NSW Greens Senator Mehreen Faruqi.

In September 2022, the Greens deputy leader tweeted that she could not mourn the passing of Queen Elizabeth II as the leader of a “racist empire built on stolen lives, land and wealth of colonised peoples”.

Senator Hanson responded, saying she was appalled and disgusted with the Greens senator’s comments, telling her to “pack (her) bags and piss off back to Pakistan”.

As the trial continued, Justice Angus Stewart heard evidence from two racism and discrimination experts about the potential impacts of the One Nation leader’s tweet.

Under cross-examination by Senator Hanson’s barrister Sue Chrysanthou SC, Deakin University’s Professor Yin Paradies disagreed that there was no basis to say the tweet would affect readers.

“That form of racism … is likely to have a negative impact on somebody vicariously because it’s a fairly strong form of racism,” he told the court on Tuesday.

“It’s very exclusionary and it’s very much about who belongs and who doesn’t belong.”

While admitting that he did not have sufficient information on the views of all who read the tweet, including those who responded angrily to Senator Faruqi, the professor said this was not unusual when researching racism.

“The thing about racism is that we need to consider it as a pattern,” he said.

The court was told Prof Paradies agreed with the Greens deputy leader’s views on colonialism, and had posted criticisms on Twitter on Australia Day in 2022 and 2023.

Last year, he posted that in 1788 “the most backward, ignorant, primitive, infantile, selfish, deluded, egoistic, sick and pernicious (mono)culture” had invaded and started annihilating one of the oldest and wisest societies on Earth.

“The vicious obliteration of this imponderably beautiful culture and the profound devastation of Country by patriarchal colonial capitalist (so-called) ‘civilisation’ continues unabated in 2023 as it has for the last 235 years,” he wrote.

Ms Chrysanthou suggested these views had warped the professor’s ability to objectively examine Senator Hanson’s tweet.

“The fact of you holding those views … has affected your approach to answering the questions about my client’s conduct hasn’t it?” she asked.

“I don’t think so,” Prof Paradies replied.

Prof Kate Reynolds of the Australian National University also gave evidence about what she described as the negative impacts of Senator Hanson’s post.

“If someone experiences a tweet like this as racism then it is likely that there will be a flow-on effect to poorer physical and mental outcomes,” she told the court.

As the trial opened on Monday, Ms Chrysanthou said her client criticised the Greens deputy’s comments rather than targeting her because of race, colour of ethnicity.

The response was meant to show Senator Faruqi was a hypocrite who insulted the Queen and the British Commonwealth but who still took advantage of all the benefits that living in Australia brought.

Senator Hanson will take the stand later on Tuesday.