"Close to one in five people Oxfam spoke to said their homes had been destroyed, and two-thirds had been displaced for ten months or longer. Almost two-thirds of the people Oxfam spoke with said that close family members had died or had been injured as a result of the conflict, and nearly half the families were looking after unaccompanied children," the charity said in a report.
The report was based on a survey, involving 1,000 displaced Yemenis.
Millions of Yemeni people are facing unemployment, mounting debt and high food prices and "run out the ways to survive," the report added.
Oxfam called on the international relief organizations and the United Nations to rapidly scale up the response and the humanitarian assistance to Yemeni population, adding that all parties to the military operation in the country should cease fire.
The war in Yemen broke out in early 2015 between the government, backed by Saudi-led coalition, and the Houthi rebel movement, supported by the armed forces loyal to former Yemeni President Ali Abdullah Saleh.
More than 6,500 people have been killed and thousands more have been wounded in the 18 months-long conflict. Over three million Yemenis have fled their homes to escape the violence of the ongoing conflict.