The "tragic" Covid-19 situation in India should raise the alarm bells for "all of us" and there will be reverberations across the region and the world in terms of virus-related deaths, virus mutations and supply delays unless the world steps up and helps the country now, the head of the UN children's agency has said.

United Nations Children's Fund (UNICEF) has sent additional critical lifesaving supplies to India, including 2 million face shields and 200,000 surgical masks.

"The tragic situation in India should raise alarm bells for all of us," UNICEF Executive Director Henrietta Fore said on Tuesday.

"Unless the world steps up and helps India now, there will be reverberations across the region and the world in terms of virus-related deaths, virus mutations and supply delays."

India also accounted for 46 per cent of global cases and 25 per cent of global deaths reported in the past week, WHO added.

UNICEF Regional Director for South Asia George Laryea-Adjei said in a statement that urgent action and steadfast leadership are indispensable to stop the catastrophe.

"Governments must do everything within their power to stop the devastation, and partners that can send assistance must do so immediately. The international community must step up without delay," Laryea-Adjei said.

"This is not just a moral imperative. The deadly new surge in South Asia threatens us all. It has the potential to reverse hard-earned global gains against the pandemic if not halted as soon as possible," Laryea-Adjei added.

UNICEF said the "scenes we are witnessing in South Asia" are unlike anything the region has seen before.

"Family members of patients are pleading for help as the region reels under an acute shortage of medical-grade oxygen. Exhausted health workers are being pushed to the brink of collapse. We are faced with a real possibility that our health systems will be strained to a breaking point – leading to even more loss of life."

Laryea-Adjei said the very low levels of vaccination in South Asia magnify the likelihood of the virus spiralling even further out of control. In almost all countries in the region, except for the Maldives and Bhutan, fewer than 1 in 10 people have been vaccinated.

"Now more than ever, we must ensure vaccines equitably reach all populations. Manufacturing must be ramped up, technology transferred, and doses equitably shared. None of us is safe until all of us are safe," Laryea-Adjei said.

Laryea-Adjei said the first wave of the pandemic caused drastic cuts in the availability and use of essential public health services in South Asia, costing the lives of an estimated 228,000 children and 11,000 mothers.

"We simply cannot let this happen again. We must do everything within our power to keep essential health, immunization and nutrition services running – and make sure women and children everywhere feel safe to use them. Viruses know no borders. We must come together now as a global community to stop the devastation and protect our children."

The UN agency said it has provided oxygen concentrators and other critically needed emergency equipment to support the immediate response in the country, while also supporting resilience-building against recurrent shocks and stresses to the health system that leave children and their families at risk.