“The relief effort in Yemen remains severely underfunded,” the UN body said in a statement.
As an example, he cited an international summit held last month to raise funds to meet the urgent humanitarian needs of millions of Yemenis.
About $1.3 billion was pledged at the event, less than a third of the $4.3 billion needed to sustain the aid programs in 2022, he said.
Since the beginning of the year, the lack of funding has forced UNFPA to limit life-saving reproductive health and protection operations in Yemen, he noted.
The agency warned that 23.4 million Yemenis, 75 percent of the population, will need some form of humanitarian assistance in 2022.
More than 4.3 million people were driven from their homes, the economy collapsed as well as the health system, the UN institution emphasized.
The United Nations Office for the Coordination of Humanitarian Affairs said in a recent report that 19 million Yemenis need food aid and 21.9 million need assistance to access critical health services.
She warned that by 2022, around 2.2 million children and 1.3 million pregnant or breastfeeding women will suffer from acute malnutrition.
The war began in 2014 when the Houthi rebels took up arms and occupied large parts of the country, including the capital Sanaa.
The following year, a Saudi-led Arab coalition intervened in the conflict to support then-President Abd Rabbu Mansour Hadi, who recently handed power to the new Presidential Leadership Council.
jcm/rob