As Yemen teeters on the brink of famine, with soaring food prices and fuel shortages, humanitarians called on Tuesday for the easing of a Saudi blockade to allow in life-saving supplies.

Although the military coalition fighting the Iran-aligned Houthi movement in Yemen's civil war has eased its month-long blockade of ports, 8.4 million Yemenis are a step away from famine, the United Nations (U.N.) said on Monday.

"We are trying to help prevent a famine from occurring," Stephen Anderson, Yemen country director for the World Food Program (WFP) told the Thomson Reuters Foundation on Tuesday.

"We will have a large-scale humanitarian catastrophe of a much larger magnitude than we currently face if commercial vessels carrying food and fuel can't get in. It will be beyond the control of the humanitarian community."

WFP, the medical charity Medecins Sans Frontieres (MSF) and the International Committee of the Red Cross (ICRC) told the Thomson Reuters Foundation the blockade has eased. "Some commercial vessels are going in but it is not enough," said Anderson. "Our worry is the prices ... People spend 70 percent of their income on food ... How will they make ends meet?"

Yemen, a nation of 28 million people, imports more than 85 percent of its food and medicine. Problems are particularly acute in hospitals, which rely on fuel to run generators, medical charities say.