UN Secretary General Antonio Guterres told the body's 193 member states on Monday that progress on women’s rights is “vanishing before our eyes".
Mr Guterres told the opening session of the Commission on the Status of Women, the UN’s largest gathering on women’s empowerment, that "gender equality is growing more distant".
"On the current track, UN Women puts it 300 years away," he said.
“Women's rights are being abused, threatened and violated around the world."
Mr Guterres spoke of the Taliban's restrictions in Afghanistan, where “women and girls have been erased from public life".
Without identifying countries, he stressed that in “many places, women’s sexual and reproductive rights are being rolled back", and girls going to school “risk kidnapping and assault”.
Mr Guterres also did not mention Iran, despite the country’s brutal crackdown on protests calling for justice for Mahsa Amini, who died in police custody in September last year.
Iran was expelled from the commission in December by a US-led resolution, which received 29 votes in favour and eight against, with 16 countries abstaining.
Iran's first female vice president after the Islamic revolution, Massoumeh Ebtekar, who also addressed the General Assembly on Monday, said Iran's expulsion from the commission was a "dangerous and inappropriate" procedure that "lacked any legal justification" and "was based on lies and the pressure of the hegemony powers and the hype created by the hired media with a purely political purpose of isolating Iran".
"The bitter irony of the story is that some countries pushing this matter have the highest number of woman murdered or incarcerated, especially among people of colour," added Ms Ebtekar.
During its two-week session, the Commission on the Status of Women is focusing on closing gender gaps in technology and innovation.
The Secretary General said the topic couldn’t be more timely because women and girls are being left behind as technology races ahead.
"Centuries of patriarchy, discrimination and harmful stereotypes have created a huge gender gap in science and technology."
Mr Guterres said women represented only 3 per cent of Nobel prize winners in those areas.
Sima Bahous, executive director of UN Women, said gender equality could not be achieved without closing the digital gap.
“We live in a world of poly-crises that make progress ever more uneven, including in the digital space, creating new and unique barriers for women and girls,” she said.
Afghan women who spoke out through YouTube and blogs, she said, had their doors marked by the Taliban, with many fleeing their country for safety.
In Iran, many women and girls continue to become targets because they take part in online campaigns, Ms Bahous said.
“Women’s rights activists cannot play their role in advancing equality if they fear reprisals," she added. "They become, in effect, invisible."
She said that if harnessed effectively, technology and innovation could be “game-changers".