The 22 richest men in the world have more wealth than every single woman in Africa over the age of 20 combined, according to Oxfam.
The 22 men - including billionaires Jeff Bezos, Bill Gates, Mark Zuckerbeg and Warren Buffett - share an estimated £975 billion ($1,268 billion), compared to £950 billion ($1,235 billion) shared between every woman in Africa, including two female African billionaires.
The Time to Care report says the gap between rich men and poor women is worsened by the number of women who provide care for children and the elderly for little or no pay.
Oxfam found women and girls were putting in 12.5 billion hours of unpaid care work every day, including looking after children and the elderly.
According to the report, the care industry contributes £8 trillion ($10.8 trillion) to the global economy - three times more than the global tech industry.
Danny Sriskandarajah, Oxfam GB chief executive, said the global economy was "chronically undervaluing" care work and was leading to inequality.
"(Its) usually done by women, who are often left little time to get an education, earn a decent living or have a say in how our societies are run, and are therefore trapped in poverty," he said.
The report urged government to crack down on tax evasion to raise money to pay for investments in water, sanitation, electricity, childcare and public healthcare.
Oxfam estimated that improved water sources in parts of Zimbabwe could save women up to four hours of work a day.
It comes as Boris Johnson hosts the UK-Africa Investment Summit in London on Monday, which brings together 21 African countries with UK and African companies.
The report was also published ahead of the World Economic Forum on Wednesday, when some of the world’s most wealthy and influential people descend on Davos in Switzerland
"If world leaders meeting this week are serious about reducing poverty and inequality, they urgently need to invest in care... and tackle discrimination holding back women and girls," Mr Sriskandarajah said.
According to Oxfam, 162 people held the same amount of wealth as the poorest half of the world's population in 2019.