UN humanitarian chief Valerie Amos has said aid must reach Typhoon Haiyan survivors more quickly.

Ms. Amos spoke out amid reports of widespread hunger and thirst and as a mayor of one of the affected areas said he would not be able to maintain law and order unless food arrived soon.

Officials are preparing to bury some of the storm's thousands of victims in mass graves in the hope of minimising the spread of disease in typhoon-hit towns.

Meanwhile Philippine Energy Secretary Jericho Petilla has warned that it could take six weeks to restore power to some areas.

People queue for aid in the area of Tacloban

Ms. Amos told reporters in Manila "The situation is dismal. Those who have been able to leave have done so. Many more are trying. People are extremely desperate for help".

"We need to get assistance to them now. They are already saying it has taken too long to arrive. Ensuring a faster delivery is our... immediate priority" she added.

Criticism has been growing that help is taking too long to arrive in areas devastated by Typhoon Haiyan last Friday.

Tacloban empties

Thousands of desperate survivors are clamouring to escape Tacloban, where clean drinking water is in short supply and scores of dead bodies lie piled up in bags outside the ruined city hall.

"There are still so many cadavers in so many areas. It's scary" the city's mayor Alfred Romualdez said, adding that retrieval teams were struggling to cope.

A gutted house in one of the worst-hit regions of Tacloban

He said "There would be a request from one community to collect five or 10 bodies and when we get there, there are 40. We need more manpower and more equipment".

"I cannot use a truck to collect cadavers in the morning and then use it to distribute relief goods in the afternoon"

UN Refugee Agency Representative Bernard Kerblat is in Tacloban.

Mr. Romualdez said the plan was to start mass burials in the nearby village of Basper on Thursday, after attempts to lay to rest some of Haiyan's victims were abandoned when gunshots halted a convoy travelling towards a communal grave.

City officials estimate that they have collected 2,000 bodies but insist many more need to be retrieved.

The UN fears that 10,000 people may have died in Tacloban city alone, but President Benigno Aquino has described that figure as "too much".

Relief efforts

US officials said relief was starting to get through, as an aircraft carrier expected to arrive in the Philippines by Friday headed toward the region.

The disaster-ravaged country has become "increasingly volatile" as people become desperate for food and water, with some resorting to force.

Aid his arriving, but is being criticised for being too slow

Coree Steadmen, Christian Aid's emergency manager in the Philippines, says "The devastation here is unimaginable. Aid workers are walking for hours and not seeing a single standing building".

"Most roads are covered with fallen trees and collapsed houses. Where roads are accessible, they are gridlocked with cars fleeing the area. Getting aid through is tough, but we are resourceful and we will find a way".