The lack of clean water in refugee camps in South Sudan has become a "major humanitarian crisis" with people exposed to diseases due to contamination, the Red Cross said Thursday.

"Severe water shortages in refugee camps close to the Sudanese border have contributed to a rise in mortality and malnutrition rates to alarming levels," the International Committee of the Red Cross (ICRC) said in a statement.

In response to the crisis, the organisation said it had launched a project to improve water access for some 37,000 people in the worst-hit camp, Yusuf Batil.

"The humanitarian situation in Yusuf Batil camp in particular is extremely worrying. Conditions are dire and survival remains a struggle," Melker Mabeck, who heads the ICRC delegation in South Sudan, said in the statement.

"Owing to the lack of clean water, people are drinking contaminated surface water. Children are especially vulnerable to death from water-borne diseases such as diarrhoea," he said, pointing out that the ICRC was expanding the camp's water infrastructure and distributing buckets for water storage.

The organisation said it was also drawing a 15-kilometre (nine-mile) pipeline to provide better access to water for the 30,000 refugees living in the nearby Jamam camp.

The ICRC first launched operations in southern Sudan in 1986, and it set up a delegation in the capital of Juba when South Sudan became an independent country in July last year.