As relief supplies finally began arriving on Friday and other evacuees scrambled for a seat on a bus out of the flooded and devastated city, there was nothing Whiticar could do but wait.

"I want to get out of here, but I need fluid pills because I just can't stand up right now," the 52-year-old diabetes sufferer said as he lay in the end zone, his feet bloated.

A military convoy with food and emergency supplies finally reached New Orleans on Friday, but a health emergency is raging after Hurricane Katrina tore in from the Gulf of Mexico earlier this week, sending deep floodwaters surging through much of the historic city.

Thousands are feared dead, and the city's hospitals are without electricity or key medical supplies, struggling to keep critically ill patients alive.

Conditions are appalling at New Orleans' two main emergency shelters -- the Superdome and the convention center -- with abandoned dead bodies on the ground or propped up in chairs.

The stench of human faeces and urine was overwhelming, and many sick people waited listlessly on the ground or in wheelchairs to be fed and evacuated. Many complained about the federal government's slow response to the disaster.

"They left us here to die," said Tony Hatcher, a 48-year-old who looked around and pointed out a woman with a half-bandaged open sore on her left leg and a boy with bad skin condition on his arms. Neither had received medical attention.