UN humanitarian chief Valerie Amos on Thursday called for more resources in Mali to save children from severe malnutrition.

"Children's lives are being blighted by a nutritional crisis which we have the knowledge and capacity to address, but we lack the funds to do everything that is needed," Amos said after a two-day visit to the west African nation.

Mali is battling a severe food crisis in the Sahel region which has been compounded by political strife after Islamic extremists seized the north five months ago, leading some 430,000 people to flee their homes.

Amos visited a refugee camp of 40,000 people in Mopti on Thursday, the last main town in the centre of the country before the Islamist-occupied zone.

During her visit she also visited a nutrition centre in the capital which has treated over 1,000 children for moderate and severe acute malnutrition since the start of the year.

Almost 150,000 children across Mali have been treated for acute malnutrition in similar facilities this year.

The food crisis, which follows a drought in 2011, has affected 4.6 million people in Mali alone.

According to a UN statement the world body has only received 46 percent of $213 million (170 million euro) requested for the humanitarian response in Mali.

"We are saving lives here, but we must do more," said Amos. "It only costs around $100 to prevent a child from dying from severe acute malnutrition. But we also have to tackle the root causes of this crisis so that mothers in Mali, and the wider Sahel region, can have confidence in the future for themselves and their children."

Even in years with good rainfall in the Sahel, a quarter of a million children die of malnutrition because of chronic poverty, poor health and lack of access to health facilities, the statement said.