According to The World Health Organisation,millions of people in South Sudan and Darfur need access to healthcare.
WHO funding for health care in Darfur is also set to run out within weeks, with no sign that donors struck by the financial crisis will renew their contributions in 2010, a senior official said.
"We know that at the end of the year, funding will dry out," said the agency's representative in Sudan, Mohamed Abdur Rab.
Meanwhile, cholera "is quite rampant in South Sudan" even though it has been stifled in recent years in Darfur, and maternal mortality is among the highest in the world in the south.
"Sudan has almost all the diseases in the medical book," Abdur Rab told journalists.
"There is an urgent need for support in south Sudan," he said. "It is grave already."
More than four million people are affected by the humanitarian crisis in the western region of Darfur.
Abdur Rab said health conditions have improved there in recent years thanks to some seven million to eight million dollars a year for often life-saving health care there.
But the progress to relatively "satisfactory" levels is already showing signs of unravelling under the onslaught of drought and malnourishment, while conditions are worse out of the international spotlight in South Sudan, he cautioned.
"There are only 10 qualified, skilled nurses in the entire South Sudan."
Just 25 percent of the eight million strong population has access to health care in the south, provided largely by aid agencies, Abdur Rab estimated.
There is just one major hospital in the southern city of Juba, while Darfur has 16 of them, he pointed out.
Maternal mortality rates in Darfur were currently around 600 per 100,000 births in Darfur.
But in South Sudan, the figure soars to more than 2,000 deaths in 100,000, according to the WHO.
Infectious diseases like diarrhoea, pneumonia, malaria and meningitis were commonplace in both regions, said Abdur Rab.