Julia Gillard and Anthony Albanese have joined a chorus of politicians criticising a truck-mounted billboard featuring Victorian premier Jacinta Allan alongside the phrase “ditch the witch”.

The billboards, which have been seen travelling through Melbourne for about six weeks, also ran AI-generated images of Allan wearing a black pointed hat and with warts on her chin, in between advertisements for a brothel.

Albanese told reporters in Canberra on Monday the “sexist” advertising campaign was “totally unacceptable and has no place in public life”.

“We want to encourage women to enter public life and it should be a contest of ideas, not personal attacks,” he said.

Speaking generally, Albanese added that there was a need to “turn the temperature down”.

“What I don’t want to do is to have a press conference in this courtyard after a tragedy,” Albanese said, citing an increased number of threats being made against politicians.

He also said some of the “personal ways” in which “mainstream media” has “characterised people in public life has just got to stop”, though he did not give specific examples.

“You can have a disagreement with people’s policy position by all means. You don’t have to denigrate people in such a personal way. It has got to stop,” Albanese said.

In a statement on social media, Gillard said she was “disgusted” to see the phrase used again after being subject to it herself during her tenure as prime minister.

“This was a slogan used against me as prime minister fifteen years ago,” she said.

“It was roundly condemned then. In the years since, my view has been that things were slowly improving for women in politics. More women are leading, sexism hasn’t gone away but it is less ferocious in the political mainstream, though social media continues to be a toxic sewer.

“I am saddened to see that improvement cast aside and this tired old trope resurrected.”

In 2011, then opposition leader Tony Abbott spoke at an anti-carbon tax rally with person holding a poster featuring the phrase “ditch the witch” visible behind him. Another poster labeled Gillard “Bob Brown’s bitch”, referencing the then leader of the Greens.

Gillard referenced the poster in her famous “misogyny speech” in Australian parliament that went viral around the world and was later voted by Guardian Australia readers as the most unforgettable moment of Australian TV history.

“I was offended when the leader of the opposition went outside in the front of parliament and stood next to a sign that said ‘Ditch the witch’,” Gillard said in the rousing speech.

On Sunday, one of the AI-generated images from the billboard was published in the Herald Sun alongside a story about a possible leadership spill against Allan, prompting the premier to release a statement saying “sexism has no place in our political debate, full stop”.

“A truck using sexist language has been driving around Melbourne as part of a secret and well-funded political campaign,” she said.

“People are entitled to disagree with me. That’s democracy. But I care that this attacks women. And I care about who’s next.”

The Age reports the trucks with billboards featuring the phrase were paid in part by Franco Puleo, the owner of the Gotham City brothel in South Melbourne.

He denied the slogan was sexist.

“[Allan] doesn’t answer questions. She’s not accountable to everything … It’s just how people are feeling. That’s what they’re resorting to,” he reportedly said.

“That’s not a political ad. It’s basically what the Victorian public feel.”

The Victorian attorney general, Sonya Kilkenny, was among several state Labor MPs who criticised the campaign on social media.

“Women in public life should not have to accept abuse and misogyny as part of the job. You can disagree with a politician. You can disagree with a government. That’s democracy. Reducing a woman to a sexist slur is not,” Kilkenny wrote.

The Victorian opposition leader, Jess Wilson, said the opposition had no involvement in the billboards, describing them as “inappropriate”.

“That sort of language, that sort of discourse, should never be used in politics. We shouldn’t see this happening on our streets,” Wilson said.

“Should we be surprised?” she said.

However the One Nation leader, Pauline Hanson, told Allan via Sky News to “suck it up, sweetheart”. She said had been called a witch “long before” Allan, including by politicians.

“Besides, Jacinta, I’ll tell you something: I’ve heard on the grapevine you won’t be there in a couple of weeks,” Hanson said.

Puleo was approached for comment.