A ship carrying 5,500 tons of flour docked in Yemen's Red Sea port of Hodeidah on Sunday, after 20-day military blockade from Saudi-led coalition, a security official at the port said.

"It's the first commercial ship docked in the port after 20 days of blockade," Houthi official Khalid Jomaey told Xinhua by phone.

He said "another aid ship carrying wheat from the United Nations World Food Programme is sailing near the port and is set to dock within hours."

The delivery is the first commercial shipment to be allowed by the coalition into the rebel-controlled seaport.

The move came one day after the coalition allowed aid flights to the rebel-held Sanaa airport.

On Wednesday, the Saudi-led coalition fighting Yemeni dominant Shiite Houthi rebels said it would allow access of humanitarian supply planes to Sanaa and ships carrying aid to the Red Sea port of Hodeidah.

Jens Laerke, spokesman of the UN humanitarian aid coordination agency OCHA, said last Friday that what really matters is that "we can get the ports in Hodeidah and Saleef open both for humanitarian aid and for commercial imports."

The coalition has been facing escalating criticisms from senior UN officials and humanitarian agencies who expressed mounting concerns over already worsening humanitarian catastrophes in the war-torn Arab country which largely depends on humanitarian aid supplies and food imports.

The coalition, which intervened in the Yemeni conflict in March 2015 to back the Sunni government of the Yemeni exiled President Abd-Rabbu Mansour Hadi, said it is planning to give clearance to aid ships only.

Around 10,000 Yemeni people, mostly civilians, were killed in the war that triggered the worst humanitarian crisis and pushed the country into the brink of famine.