More children in South Asia are struggling due to severe water scarcity made worse by the impacts of climate change than anywhere else worldwide, the United Nations said Monday.

"A staggering 347 million children under 18 are exposed to high or extremely high water scarcity in South Asia, the highest number among all regions in the world," the UN children's agency said in a report.

The eight-nation region, comprising Afghanistan, Bangladesh, Bhutan, India, Nepal, Maldives, Pakistan, and Sri Lanka, is home to more than one-quarter of the world's children.

"Climate change is disrupting weather patterns and rainfall, leading to unpredictable water availability," the UN said in its report.

The report cites poor water quality, lack of water, and mismanagement such as over-pumping of aquifers, while climate change decreases the amount of water replenishing them.

"When village wells go dry, homes, health centers, and schools are all affected," UNICEF added.

"With an increasingly unpredictable climate, water scarcity is expected to become worse for children in South Asia."

At the UN COP28 climate conference in December in Dubai, UNICEF said it will call for leaders "to secure a livable planet".

"Safe water is a basic human right," said Sanjay Wijesekera, UNICEF chief for South Asia.

"Yet millions of children in South Asia don't have enough to drink in a region plagued by floods, droughts and other extreme weather events, triggered increasingly by climate change".

Last year, 45 million children lacked access to basic drinking water services in South Asia, more than any other region, but UNICEF said services were expanding rapidly, with that number slated to be halved by 2030.

Behind South Asia was Eastern and Southern Africa, where 130 million children are at risk from severe water scarcity, the report added.