Zack Polanski has called for an inquiry into the "culture and behaviour" of the media following the death of former Cambridge professor Jason Arday.
The Green Party leader said it was time the press was "sorted out" after the 41-year-old academic was found dead at an address in Battersea, south London, on Friday.
Mr Polanski has since signed a letter to Andy Burnham calling for an inquiry into how to "ensure a responsible press" following the tragedy.
The London Assembly member has also urged the Government to ban foreign ownership of national newspapers and branded the Independent Press Standards Organisation (Ipso) a "toothless" organisation.
His remarks come as members of his own party call on ministers to ensure the "full completion" of the Leveson inquiry and place the British press under a “genuinely independent and recognised regulator with effective enforcement powers”.
Green Party members have also tabled a motion calling for the proposed new regulator to monitor “harassment” they claim comes from news stories, as well as "map and address" instances of racism and ableism.
Following Mr Arday's death, Mr Polanski said the academic was "subject of sustained and malicious media attacks which were no doubt more vicious because he was black".
He added: "We must now reflect on the impact of a trial by some of the media and online on someone under extreme pressure."
Mr Arday became the University of Cambridge's youngest ever black professor when he took up the role in March 2023.
He stepped down as professor of sociology of education at the university on August 4, amid accusations of plagiarism.
Cambridge announced last week that it was launching an investigation into Mr Arday's appointment, as well as his tenure at the university.
He resigned within hours of the university announcing the investigation, pointing to an "unrelenting level of public scrutiny".
THE GREEN PARTY - READ THE LATEST:
- Green councillors consider pigeon contraception to tackle bird droppings problem
- Green councillor charged with assaulting five people including three police officers
- 'Queer migrant’ Green MSP under fire after saying ‘rape is a spectrum’
The Prime Minister described Mr Arday's death as a tragedy on Saturday, urging a “moment of reflection” and advising people “not to rush to judgment”.
But the Green Party leader blasted Mr Burnham's remarks as "really spineless", saying the Prime Minister "utterly fails to recognise the moment to tackle the press".
“I don’t think it would be ‘rushing to judgment’ to see that the press hounding people - especially people of colour - has been going on for a very long time," Mr Polanksi wrote on social media.
Replying to a story posted by the Daily Mail about Britain's heatwave-filled summer, he said it was "time we sorted out the press".
"Constant misinformation to protect their donors and fossil fuels is destroying lives and our planet. The Government must step up and stop being cowardly," he wrote.
On Tuesday, the Green Party leader attended a vigil for the academic in Trafalgar Square.
He posted a video showing attendees holding placards and flowers in tribute to the 41-year-old, alongside the caption: "Rest in Power, Professor Jason Arday."
Free Speech Union founder Lord Young criticised Mr Polanski's comments, telling The Telegraph: “For the Green Party to pre-empt the inquest into [Mr Arday’s] death and weaponise it to pursue their anti-free speech agenda is both cynical and exploitative.
“The British press does not need to be ‘sorted out’. Scrutinising powerful and influential figures and holding them to account, including Zack Polanksi, is precisely what it should be doing.”
Our Standards: The GB News Editorial Charter
