The Sudanese Coordination of Civil Democratic Forces (Taqaddum) appealed for the international community to urgently intervene to aid the people caught in the fighting between the army and Rapid Support Forces (RSF).
It called on it to agree on routes to deliver humanitarian aid to all affected regions in the country.
Headed by former Prime Minister Abdalla Hamdok, Taqaddum met overnight on Saturday to discuss the humanitarian catastrophe caused by the ongoing war that erupted on April 15.
It also addressed the weak international response to the humanitarian crisis.
Hamdok underscored the importance of humanitarian assistance and the impact of the war on Sudanese people inside the country and abroad.
Taqaddum called on the warring parties to guarantee the delivery of aid. The gatherers agreed to form a platform to coordinate the humanitarian response, attract foreign support and draw the world's attention to the catastrophe in Sudan.
Taqaddum is expected to issue a "joint appeal" that sets the operational steps to confront the humanitarian crisis and unite international efforts to support the Sudanese people during the crisis.
Taqaddum member Khaled Omar Youssef described the humanitarian situation in Sudan as "catastrophic", warning that famine is imminent if the war continues.
The meeting stressed the importance of the formation of a broad team that would coordinate efforts, urge the international community to provide humanitarian aid and remove the obstacles that are hindering relief efforts.
He warned that the war has "divided the Sudanese people in an unprecedented way".
Millions of people are paying the price, but the humanitarian crisis and its impact must not be sources of division and differences, he declared.
International and regional efforts on Sudan are focusing on addressing the humanitarian file and reaching a ceasefire between the army and RSF.
The army had previously approved the delivery of aid, but limited the routes for their delivery through airports, marine ports and land borders in regions held under its control.
Meanwhile, the RSF, which holds four major states in Darfur and Al-Jazirah, has demanded the delivery of aid to regions under its control through an agreement between relevant parties and international organizations.
The army has been accused of obstructing the delivery of aid to hundreds of thousands of civilians trapped in conflict zones in Darfur and the capital Khartoum.
The United Nations’ Food and Agriculture Organization (FAO) warned last week that almost 18 million people in Sudan are facing acute food insecurity - the highest number ever recorded during a harvest season.