In a withering statement, Ms Banks took aim at the “scourge of cultural and gender bias” in politics and society.
In recent years, Australian female MPs have accused male counterparts of “misogyny” and “slut-shaming”.
Amid wide-ranging and chaotic infighting last week, the government faced an allegation that male party figures had “stood over” female MPs in a bid to secure enough signatures to topple Mr Turnbull. Others denied the assertion.
Earlier this year, the government launched a national inquiry into workplace sexual harassment.
Who did Ms Banks criticise?
The Liberal Party MP, who holds a marginal seat in Melbourne, did not make reference to specific incidents.
However, she said in a statement: “I will always call out bad behaviour and will not tolerate any form of bullying or intimidation. I have experienced this both from within my own party and the Labor party.”
“In anticipating my critics saying I’m ‘playing the gender card’ – I say this. Women have suffered in silence for too long and in this last twelve months the world has seen many courageous women speak out,” she added.
A supporter of Mr Turnbull and Julie Bishop – who was replaced as party deputy last week – Ms Banks also made a more general criticism about the political turmoil, rebuking unnamed figures with “mean-spirited grudges intent on settling their personal scores”.
She said she would support new Prime Minister Scott Morrison and party deputy Josh Frydenberg.
How have others responded?
Mr Morrison said he had “no truck with bullying or intimidation in whatever form it is”.
“I have laid down the law to my ministry and to the parliamentary secretary ranks of my government,” he said on Wednesday.
Minister for Women Kelly O’Dwyer, who called herself a friend of Ms Banks, said workplace bullying “whether on the shopfloor, or in our nation’s Parliament, [was] totally unacceptable”.
“I deeply regret the decision that Julia has made today… and the circumstances that have led to her decision to leave politics”.
What has been controversial previously?
Under Tony Abbott’s leadership in 2013, the centre-right government was criticised for having just one woman in a 19-member cabinet – although it has since added more.
Allegations of gender-based bullying have also hit Labor: one MP, Emma Husar, asserted on Wednesday that her career had been ruined by malicious “slut-shaming”.
In recent times, Australian politics has also heard:
Julia Gillard, as prime minister in 2012, accuse Mr Abbott of “misogyny” in a parliamentary speech that went viral;
Sarah Hanson-Young, a senator, say she had been “slut-shamed” by a male political opponent;
Reports that Ms O’Dwyer was asked to consider expressing milk to avoid missing parliamentary duties in 2015, prompting a backlash.