The cost of life-saving treatment for the most severely malnourished children is set to jump by up to 16% due to the ongoing war in Ukraine and pandemic disruptions, according to the United Nations' children's agency.

The raw ingredients of a ready-to-use therapeutic food (RUTF) have leapt in price amid the global food crisis sparked by the war and pandemic, UNICEF said.

Without further funding in the next six months, 600,000 more children may miss out on the essential treatment, which is a high-energy paste made of ingredients including peanuts, oil, sugar and added nutrients.

UNICEF said a carton of the specialized nutrition containing 150 packets – enough for six to eight weeks to bring a severely malnourished child back to health – cost about $41 on average before the up to 16% price rise. It will need about $25 million to cover the added cost, the agency said.

Alongside the wider pressure on food security, including climate change, the price rise could lead to "catastrophic" levels of severe malnutrition, the children's agency warned in a statement.

"The world is rapidly becoming a virtual tinderbox of preventable child deaths and child suffering from wasting," said UNICEF Executive Director Catherine Russell.

Severe wasting, when children are too thin for their height, affects 13.6 million children under 5 years old, and results in one-in-five deaths among this age group.

Even before the war and pandemic, two-in-three did not have access to the therapeutic food needed to save their lives, UNICEF said.

The World Bank's chief had also warned in April a record rise in food prices would push hundreds of millions of people into poverty and lack of nutrition if the war continues, saying that the world is facing a "human catastrophe" from a food crisis in the wake of the Ukraine war.