Oscar winner George Clooney Thursday said President Barack Obama would press China's President Hu Jintao when they meet in Seoul this month for action on averting a humanitarian disaster in Sudan.

Clooney met Obama two days after returning from a clandestine trip to Sudan's mountainous South Kordofan region, which is facing famine due to bombings by government forces that have impeded agricultural production.

He argued that China, Khartoum's top partner, may be susceptible to economic rather than moral arguments as it was experiencing pain from a shutdown in oil shipments due to the rift between Sudan and South Sudan.

"China, (which) gets six percent of its oil imported from the Sudan, suddenly it affects their economy," Clooney told reporters at the White House, saying that US coordination with Beijing could alleviate the situation.

"There is a moment that we can appeal for China not on a humanitarian issue ... this is an opportunity ... on a high level to work together and help effect their own economic interests.

"The president has a meeting with president Hu in two weeks and said he would have a discussion with him about that very specific issue."

South Sudan became independent in July following two decades of war.

But a new conflict broke out soon afterward in South Kordofan and nearby Blue Nile state, with Khartoum fighting insurgents once allied to the former rebels who now rule South Sudan.

Obama and Hu are both due to take part in a Nuclear Security Summit in Seoul on March 26-27. The White House has yet to confirm they will hold one-one-one talks, but they frequently meet at international summits around the world.

On Wednesday, the United States urged Sudan to allow in food shipments immediately to avert a humanitarian disaster, as Clooney accused the Khartoum government of war crimes.

The "Ocean's Eleven" star said he saw hundreds of people running to the hills or hiding in caves due to the omnipresent buzzing of Antonov planes, from which Sudanese forces manually dump notoriously inaccurate bombs.

Clooney, a longtime activist seeking to end what the United States has called genocide in Sudan's western Darfur region, said South Kordofan was "ominously similar."

He argued that President Omar al-Bashir and his aides are "proving themselves to be the greatest war criminals of this century by far."