At a press conference in Amman, Jordan on Sunday, Geert Cappelaere, the regional director for the Middle East and north Africa at United Nations children's agency Unicef, called on the warring parties to join proposed peace talks later this month and agree to a ceasefire.
Three-quarters of Yemen's 29 million people are food insecure, 1.8 children suffer from malnutrition and 400,000 children under age 5 are in the worst stage of malnutrition - without intervention they might die.
He said the figures were "a reminder for all of us to realise how dire the situation has become".
On Wednesday, the UN Special Envoy for Yemen Martin Griffiths announced his commitment to bringing the warring Yemeni parties to the negotiation table within a month, stressing that dialogue remains the only path to reach an inclusive agreement in the country.
But the war has caused thousands of civilian deaths and left millions on the brink of starvation, ramping up pressure on the UK to stop arms sales to the kingdom.
"An end to the conflict is. a much-needed step but it needs to be complemented with investment and governance of this country that puts the interest of the people at the center and the interest of the children at the core of politics", Cappelaere said.
The alliance of Sunni Muslim states led by Saudi Arabia and the United Arab Emirates intervened in Yemen in 2015 to oust the Houthis and restore the internationally recognized government. Some rights groups estimate the toll could be five times higher.
Loud explosions were heard across Yemen's Red Sea coastal city of Hodeidah on Friday evening, as pro-government forces began a wide-scale military offensive against the Houthi rebels.
Geert Cappelaere told The Associated Press in an interview from Yemen that recent USA calls for a cease-fire are imperative to ending the almost four-year war, which pits a Saudi-led coalition against Iran-aligned rebels known as Houthis.
Thirteen pro-government troops were killed, according to medical sources in Aden and Mokha, where their bodies were transported.
Yemen's internationally recognised government On Thursday welcomed a call from the USA for peace in the conflict-torn country, state-run news agency Saba said. "Subsequently, coalition air strikes must cease in all populated areas", said Mike Pompeo, US secretary of state, on Wednesday.
The port is the entry point for more than 70 percent of imports into the impoverished country.
A previous attempt to take the city in June ran into difficulties and was halted ahead of UN-led peace consultations in Geneva which collapsed in September after the Houthis failed to show up. Yemeni government officials said on Tuesday that the coalition had sent more than 10,000 new troops towards the battleground city.