Ms Plibersek, a leading member of the 'squad' and now the opposition's foreign affairs spokeswoman, said on Wednesday some of the criticism levelled at Ms Gillard when she was prime minister had a ''genuine pornographic and violent edge to it'', and was of an intensity that Australians had never seen in public life.

But Ms Plibersek said she and female colleagues like then minister Nicola Roxon had not responded earlier because they had believed it would risk drawing attention and supplying ammunition to ''the rants of nutters'' and deflect attention from serious government policy.

She now believed a much more robust response should have been employed earlier, and she and her colleagues should have ''called out'' the most virulent sexists as prominent Liberals, including Tony Abbott, began appearing in front of placards accusing Ms Gillard of being a ''witch'' and worse.

''In large part, the feminists of the hit squad arrived on the ground after the game was over,'' Ms Plibersek said.

''Julia Gillard, I think, felt very much alone.''

Ms Plibersek, Ms Roxon and fellow Labor MP Deb O'Neill were named the ''handbag hit-squad'' by Liberal MP Kelly O'Dwyer during a 2012 exchange in the federal parliament after Ms Plibersek called then opposition leader Tony Abbott a sexist.

Ms Plibersek was speaking on Wednesday at the Melbourne launch of author and former Victorian state Labor minister Mary Delahunty's latest book, Gravity: Inside the PM's office during her last year and final days.

Ms Delahunty said she had written the book in an attempt to explain who Ms Gillard really was: a woman who became prime minister late one night, unexplained to the wider public, and who had lost the prime ministership three years and three days later, still unexplained.

She had discovered a woman who was very private, yet was intensely interested in people, good for a laugh, highly intelligent and tough as nails. She recalled that at a time when Ms Gillard was trying desperately to rally support among colleagues to save her imperilled leadership, she had taken time out to ask ''How's Joan?'' - an inquiry about Victoria's former premier, Joan Kirner, who was ailing. Ms Kirner was among a number of Labor luminaries attending the book launch on Wednesday.

''I wanted to understand what history would say about our first female prime minister,'' Ms Delahunty said. She had become alarmed that history would be informed by the preponderance of often sensationalised, and skewed newspaper articles, ''roaring and ranting'' headlines, cartoons and online blogs about Ms Gillard.

While writing the book, she could scarcely believe the ''toxic'' nature of some cartoons in particular, and had come to believe that ''a new political template using sexism'' had enveloped the Gillard period.

Ms Delahunty said a political career for women was still worth it, but it should be understood that while politics could be both a noble profession, it could also be very toxic.

''I hope our next female prime minister gets the support that we were so slow to come to,'' she said.

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