Nine immigrants have died among around 300 abandoned by smugglers in the scorching Sudanese-Libyan desert, with the others in poor condition, Khartoum's army says.

"They were on their way to Libya as illegal immigrants," spokesman Sawarmi Khaled Saad told AFP on Wednesday.

"The smugglers left them in the desert... on the border between Sudan and Libya," he said, adding that all of the dead were Sudanese.

The others are from various nationalities and include Ethiopians, Eritreans, Pakistanis and Bangladeshis, Saad said.

Separately, the defence ministry website said that the total number of victims was 319 and that the rescue was by a joint force of Sudanese and Libyan troops.

"Nine of them died and the others are in a bad condition. They are getting treatment and being transferred to Dongola," the statement said, referring to a town about 500 kilometres northwest of Khartoum.