A landmark survey has revealed shocking accounts of escalating online violence against girls and women across more than 20 countries, with respondents exposed to explicit messages, pornographic photos, cyberstalking and other forms of internet abuse.

Attacks are most common on Facebook, followed by Instagram and WhatsApp, according to the Plan International survey.

The charity, which focuses on equality for girls, surveyed 14,071 teenagers and young woman aged 15-25 across 22 countries, including Australia, Canada, Brazil, Benin, Japan, Zambia and the US between 1 April and 5 May.

The poll found that in Australia, 65% of 1,000 respondents had been exposed to a spectrum of online violence, compared with the global figure of 58%. Half of those who had experienced harassment in Australia suffered mental and emotional distress as a result. One in five Australian girls and young women had feared for their physical safety due to online threats.

Across all girls and women surveyed, the most common type of online harm was abusive and insulting language (reported by 59% of respondents), followed by deliberate embarrassment (41%) as well as body shaming and threats of sexual violence (both 39%).

Globally, attacks are most common on Facebook, where 39% have suffered harassment, followed by Instagram (23%), WhatsApp (14%), Snapchat (10%), Twitter (9%) and TikTok (6%). One in five (19%) of respondents who had been subjected to online violence significantly reduced their use of social media, while one in 10 (12%) changed the way they expressed themselves online. Meanwhile, 44% of all the girls and young women surveyed said social media companies needed to do more to protect them.

One in five (22%) of those surveyed said they or a friend had been left fearing for their physical safety due to online harm, while 39% reported low self-esteem, and 38% said the harassment caused mental and emotional stress. Abuse caused problems at school for 18% of respondents.

When asked who was perpetrating the violence, 40% said they experienced harassment from people at school or work, 29% said a friend and 16% former partners. Meanwhile, 38% said they had been harassed by anonymous social media users.

For girls who identified as LGBTIQ+ online, close to half said they experienced harassment due to their sexual or gender identity, and 60% of girls who identified as an ethnic minority said they had been specifically targeted because of this.

The chief executive of Plan International, Susanne Legena, said while online platforms had given voice to millions of young people, it was also “where the worst of humanity has manifested”.

“Violence has flourished to the point where for many girls, abuse is a day-to-day reality,” Legena said. “When you consider the shockingly high number of girls worldwide are subject to abuse every time they participate in discussions online, in addition to being hassled and harassed on the street when they step outside their homes, and that harassment is a form of violence, there is no space – virtual or other – where girls are safe and free from violence.

“As a result, girls are reporting long term mental health problems and in many cases, are opting out of expressing themselves and their opinions for fear of retribution, and sometimes removing themselves from these platforms altogether.”

In her foreword to the report, Free to be online?, the executive director of the South Sudan gender equity agency Resilience Organisation, Kevin Abalo, said there was only so much an individual could do to protect themselves.

“We must all campaign for change, forcing governments and technology companies to put protection in place,” she wrote. “Girls and young women are sick of being harassed and in some cases driven away from all the opportunities that, in a better world, the internet provides. This is a human rights issue.”

Caitlin McGrane, the leader of the enhancing online safety for women project at Gender Equity Victoria, said the research was important, bringing a much-needed focus on the extent and impact of online harassment on young women around the world.

Social media had never been designed as a safe space for women and girls, she said. For example, the founder of social media platform Facebook, Mark Zuckerberg, created the website off the back of a website he made called “FaceMash” that allowed university students to upload photos of women on campus and rank their attractiveness.

“Online is particularly violent for young people from marginalised backgrounds or identities,” McGrane said. “Online platforms like Facebook and Instagram need to be listening to young women experiencing harassment and taking more action when it is reported. These actions need to include taking down posts, comments and messages that are harassing and removing offenders from the platform.

“It is also vital we take a preventative approach to online harassment by teaching young people, especially young men, about respectful, appropriate communication.”