Amnesty International has rounded on Twitter for not doing enough to protect women after a Belfast Telegraph survey showed that more than three-quarters of female MLAs had experienced abuse online.
Northern Ireland's five main parties have expressed serious concern after our survey showed that a quarter of women MLAs had been sexually harassed during their political lives.
Our investigation found 70% had sexist remarks made to their face by men, and 78% have experienced sexism on social media.
First Minister Arlene Foster said it was "vital that a light is shone on attitudes towards female representatives".
Grainne Teggart of Amnesty International said Twitter had implemented only one of 10 recommendations it had made to the social media giant two years ago to protect women from online abuse and violence.
Ms Teggart said: "Twitter has long been a toxic and hostile place for women who all too frequently experience threats and harassment related to their gender, role in public life, ethnicity or sexual orientation.
"We cannot allow the trolls to win. Despite the claim to be on women's side, Twitter is failing to take concrete steps to address and prevent violence and abuse on its platform.
"It regrettably comes as no surprise that three-quarters of our female MLAs have experienced sexism online. Often online abuse translates to offline abuse and vice versa, perpetuating a culture of misogyny and violence against women."
Justice Minister Naomi Long said: "Shamefully, both sexism and misogyny are alive and well, and act as a barrier to many women coming forward to contribute to political and public life.
"It is most prevalent on social media, where Twitter's system for reporting abuse is particularly ineffective, and reports of abuse not taken seriously. This inaction is letting women down."
Mrs Foster said: "In the absence of action from social media platforms, there remains a need for proper regulation to help combat this scourge."
UUP leader Steve Aiken said the accounts of harassment and sexism given by female MLAs to the Belfast Telegraph were "sadly, not surprising".
He said: "The targeting of female elected representatives has disgracefully been a common feature of politics, particularly in the new era of social media.
"This should not, and cannot, continue to be tolerated and the culture that allows such unacceptable behaviour to exist must be challenged."
Sinn Fein MLA Emma Sheerin said: "Sinn Fein will continue to work to ensure equal opportunities exist for females in politics, and that misogyny and all forms of discrimination are consigned to the bin. I would encourage any woman who has been a victim of sexual harassment or abuse in their workplace to report it to the relevant authorities."
An SDLP spokesperson said: "The testimony from female MLAs is deeply shocking and clearly demonstrates that misogyny is rife in political life.
"We are committed to playing our part in stamping it out for good and making public life a safer and more welcoming space for women. We'll also be working with women in the party to ensure that we're providing as much support as possible to help them carry out their public duties."