"The Darfur summit has been postponed because some of the participants were not available," Egyptian Foreign Minister Ahmed Abul Gheit told reporters.
Egypt was to host a mini-summit in the Red Sea resort of Sharm el-Sheikh on April 20 with other leaders from Chad, Libya, Nigeria and Sudan to try to find a solution to the Darfur crisis.
Darfur rebel groups had already rejected the idea of the summit, charging that its only purpose was to offer support to the Sudanese government.
A similar five-way meeting over Darfur -- also without the presence of the rebel movements -- was held in Libya in October last year but failed to yield any significant results.
According to a British parliamentary report, some 300,000 people have died in Darfur from the combined effect of war and famine since a rebellion broke out more than two years ago and was brutally repressed by Khartoum.
On April 1, the UN Security Council passed a resolution referring Darfur war criminals to the International Criminal Court in The Hague, in a bid to pressure Khartoum into reaching a political solution to the conflict.