Three UN agencies have expressed deep concern about limited funding to assist South Sudanese refugees in Sudan.

The World Food Program, UNICEF and the UNHCR say more than 50,000 displaced people have crossed the border to Sudan since the beginning of the year.

But with the limited funding, the agencies say limited funding has affected their ability to respond to emergency needs of the new arrivals.

In a joint statement, the UNHCR says more than 80 percent of the humanitarian requirements for 2016 have not been funded, meaning the agency cannot meet needs worth 128 million US dollars.

Unicef says almost 90 percent of its projects in hygiene and protection have not been funded, which makes a gap of more than 100 million US dollars.

On the other hand, the WFP says it is currently facing a 12-month funding shortfall of 181 million US dollars. 19 million would be used to meet the needs of the South Sudanese refugees through its Protracted Relief and Recovery Operation.

The agencies have called for more funding, warning that the situation is worrying since it coincides with a period of higher food insecurity in parts of South Sudan.