The Saudi-led coalition fighting in Yemen announced a suspension of border crossing via air, marine and land routes following a ballistic missile fired from Yemen targeting Saudi capital Riyadh on November 6.
The Saudi-led coalition was not immediately available for comment.
"We have some 21 million people needing assistance and seven million of those are in famine-like conditions and rely completely on food aid", United Nations humanitarian coordinator for Yemen Jamie McGoldrick said.
Jamie McGoldrick of the UN Office for the Coordination of Humanitarian Affairs said Tuesday the world body is aware of an announcement that the coalition was allowing deliveries to two ports in southern Yemen, AP reported.
McGoldrick was speaking to reporters in Geneva by phone from Amman, because he said flights into Sanaa were blocked.
Yemen's national airline said on Tuesday a commercial flight had landed at Aden global airport after acquiring security permits, a step that will ease a blockade on one of the poorest Arab nations.
Iran denies arming the Houthis and blames the conflict in Yemen on Riyadh.
"We would ask that the coalition opens all the seaports as a matter of urgency and allows humanitarian and other supplies to move, as well as the movement of aid workers", he said.
Amid "the state of deadlock" in Lebanon following the resignation of its prime minister, the prelates said they were concerned that he had not yet returned to Lebanon, stressing that this was "necessary for the sake of dignity, sovereignty and stability".
He also said that the more the blockade tightens, the more the Houthis will develop their abilities to "respond to the assault of the enemy".
It says: "The first step in this process will be taken within 24 hours and involves reopening all the ports in areas controlled by" Yemen's internationally recognized government, which the coalition backs.