The new appeal report warns that only around five percent has been funded of an estimated $1.1 billion needed for the previous humanitarian aid plan for 5.5 million people.

"With new and increasing needs, additional resources are urgently required," the report said.

The new appeal would target the most vulnerable 1.1 million people, with an emphasis on women and girls "who face higher risks of gender-based violence, food insecurity and lack of access to reproductive health," it added.

According to the UN, more than 6.3 million people are in urgent need of assistance in the areas hardest hit by the magnitude 7.7 earthquake on March 28, which killed more than 3,600 people.