Geneva, June 20 (IANS): The UN on Saturday appealed for $1.6 billion to help millions of people in war-torn Yemen while warning of a "looming catastrophe".

"The money is needed to address the "constantly increasing humanitarian needs in Yemen", Gulf Daily news quoted Jens Laerke, spokesperson for the UN's humanitarian agency, as saying.

Laerke said more than 21 million people -- 80 percent of the population -- were in need of some form of humanitarian aid.

At the launch of the aid appeal, UN Under-Secretary for Humanitarian Affairs Stephen O'Brian warned that Yemen was facing a looming humanitarian catastrophe.

"Millions of families no longer have access to clean water, proper sanitation and basic health care; deadly diseases such as dengue and malaria have broken out and supplies for acute trauma care are running dangerously low," O'Brian said.

Only about $200 million of the needed cash has been received so far, the UN said.

Saudi Arabia, which has been carrying out airstrikes in Yemen since March 28, pledged $274 million towards the UN appeal in April. However the UN has not received any of the promised funds from Saudi Arabia, Laerke said.

Yemen has been wracked by conflict between Houthi rebels and troops loyal to exiled President Abedrabbo Mansour Hadi, who fled to Saudi Arabia in February.

The rebels have overrun much of the country and, along with their allies among forces loyal to deposed president Ali Abdullah Saleh, have been the target of Saudi-led air strikes.