Sudan's war is deepening one of the world's worst hunger crises, as fighting between the army and the Rapid Support Forces intensifies in North Kordofan and parts of Blue Nile state.

The renewed fighting is pushing thousands of civilians to flee at planting time, compounding a displacement emergency that has already uprooted more than 12.4 million people. About 24.6 million people — roughly half the population — face acute food insecurity.

The United Nations' response plan for Sudan, costed at $2.9 billion, is only about 41 per cent funded, leaving aid agencies warning that food, medicine and shelter will run short for many communities cut off by the fighting.

Humanitarian groups say safe access for convoys remains the central obstacle: without it, even funded aid cannot reliably reach the states where hunger is now most severe.