"We are monitoring these developments and we are trying to see whether that actually takes place on the ground", United Nations spokesman Farhan Haq told reporters at United Nations headquarters in NY.
The Saudi-led coalition fighting rebels in Yemen has pledged to reopen the country's main airport, as well as two main ports.
It did not specify when or if it would ease a blockade on commercial traffic.
The UN and other advocacy groups have pressured the Saudi-led coalition to allow aid into Yemen through the Hodeida and Saleef seaports, which the coalition had said they would reopen. "If that were to happen that would be a very welcome and critically important development".
The UN says a continuation of the two-week blockade would make Yemen's war-battered population more vulnerable to cholera and starvation.
Aid group Save the Children welcomed the coalition's announcement but said opening the port and airport would be "nowhere near enough to avert a potential starvation in Yemen".
The U.N. humanitarian chief in Yemen says the closure of the country's main airport and two seaports by a Saudi-led coalition has threatened gains made in containing cholera and the risk of starvation in the war-torn country.
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"The UN has been notified through our usual contacts in Riyadh that the regular passenger flight operated by the United Nations Humanitarian Air Service can fly to Sana'a from Amman starting tomorrow", Jens Laerke, the spokesman for the UN humanitarian office, told reporters in Geneva.
Houthis have been controlling much of Yemen's north by force, including the capital Sanaa since 2014.
In 2015, Saudi Arabia and its allies joined the Yemeni government's fight against the rebels.
The United Nations says some 7 million Yemenis are on the brink of starvation and 945,000 have been infected since April with cholera.
The war has killed more than 10,000 Yemenis, mostly civilians, and displaced over 3 million, according to humanitarian agencies.
The UN Food and Agriculture Organization (FAO) says Yemen is highly dependent on imported wheat for its basic needs.