Britain, the US and other mostly Western countries condemned abuses by Sudan's warring factions and called on the UN Human Rights Council to step up monitoring of the conflict at an emergency meeting of the body on Thursday.

Sudan's ambassador to the body hit back at the suggestions of outside involvement, described the conflict as an internal affair and called for "African solutions for African problems".

Battles between Sudan's army and rival paramilitary forces have killed hundreds and wounded thousands, disrupted aid supplies, sent refugees fleeing abroad and turned residential areas of Khartoum into war zones since mid-April.

UN human rights chief Volker Turk told the 47-member council that both sides had "trampled" on international humanitarian law.

Four countries - Britain, the United States, Germany and Norway - are leading efforts to pass a motion to give the UN's Sudan expert more powers to monitor and document reports of abuses. A vote is expected later on Thursday.

"There must be accountability for the horrific events taking place," Britain's Minister of State for Development and Africa Andrew Mitchell told the council by video link.

"This is the moment to send a clear message to the parties of the conflict that the world is watching and expects them to deliver for the people of Sudan," US ambassador Michele Taylor said.

Sudan's ambassador Hassan Hamid Hassan poured scorn on the whole meeting.

"Why are you rushing to hold such an ad hoc session in this timing, especially since it has not received the support of any African or Arab countries," he asked.

"What's happening in Sudan is an internal affair and what the SAF (Sudanese Armed Forces) are doing is a constitutional duty to all armies in all countries in the world."