Liberal MP Julia Banks has announced she will not recontest her marginal seat of Chisholm in an incendiary statement blasting the “cultural and gender bias, bullying and intimidation” of women in politics.

In a blow to Scott Morrison’s attempts to heal the wounds of the Liberal party divided by the successful conservative push to remove Malcolm Turnbull, Banks revealed she had experienced intimidation and bullying both from within her own party and from the opposition Labor party.

On Wednesday the government’s problems triggered by Turnbull’s resignation deepened, with Labor warning it will not grant the Liberals a pair in the House of Representatives to compensate for his absence during the Wentworth byelection. (Pairing is a parliamentary convention whereby a member agrees to miss a vote when an MP from the opposing side cannot attend in extenuating circumstances, such as illness.)

A few people have been asking about whether Labor will offer to “pair” Malcolm Turnbull during the Wentworth by-election. There’s a long explanation but in short “No.”#auspol — Tony Burke (@Tony_Burke) August 29, 2018

Banks – who won Chisholm in the 2016 election with a wafer-thin margin of 1.24% after Labor held the seat for 18 years – noted in the letter she was elected “under the leadership of Malcolm Turnbull”.

She said she and her constituents had wanted Turnbull to remain prime minister and Julie Bishop to remain deputy Liberal leader.

Banks said she had always put Australia’s national interest “before internal political games, factional party figures, self-proclaimed power-brokers and certain media personalities who bear vindictive, mean-spirited grudges intent on settling their personal scores ... Last week’s events were the last straw”.

She described bullying and intimidation as a “scourge” in politics, the media and business, and warned those who would accuse her of “playing the gender card” that she will continue to fight for gender equality because women have been “silent for too long”.

While gathering signatures to force a party-room vote on Turnbull’s leadership, conservatives were accused of intimidating several women MPs and senators to support the push.

Banks said her constituents know she would “always call out bad behaviour and will not tolerate any form of bullying and intimidation”, revealing she had “experienced this both from within my own party and from the Labor party” but declining to give details.

Kelly O’Dwyer, the cabinet minister and neighbouring MP in Higgins, tweeted her support for Banks’s comments on bullying.

Julia Banks is my neighbour in the seat of Chisholm. She is a terrific member of the Liberal team and a good friend. Bullying in any workplace, whether on the shopfloor, or in our nation’s Parliament, is totally unacceptable. pic.twitter.com/xyrIFacKYP — Kelly O'Dwyer (@KellyODwyer) August 29, 2018

Banks said she would take a few days leave before parliament returns on 10 September, because of the “enormous emotional toll” the period of leadership instability had caused.

The member for Chisholm heaped praise on Turnbull as an “inspiring and visionary leader of such intellect and integrity, whose legacy is strong economic leadership”.

She promised to work hard for the people of Chisholm and “support the good leaders of the Liberal party” including Morrison, deputy leader and treasurer Josh Frydenberg and the new candidate for Chisholm.

At a doorstop in Perth, the finance minister Mathias Cormann said that Banks was a “good contributor” and he was “obviously disappointed” she had decided to quit.

Asked if he needed to apologise to Banks on behalf of conservatives, Cormann – who personally collected signatures for the spill petition – said he always treats colleagues “with courtesy and respect and would never condone anyone doing otherwise”.

On Thursday the Liberal senator Linda Reynolds told the Senate she was “deeply saddened and distressed” by events in her party, saying the behaviour of some had “no place in [her] party or this chamber”.

After Banks’ announcement Reynolds told Guardian Australia: “I greatly respect my friend and colleague Julia Banks who is an outstanding local member and a woman of great integrity.”

Chisholm is the Liberals’ most marginal seat in Victoria, a progressive state considered likely to punish the move to ditch Turnbull.

As the only seat the Coalition took from Labor in the 2016 election, Chisholm was pivotal in helping Turnbull form majority government.