Eight people have been killed in the typhoon-ravaged central Philippines after thousands of Haiyan survivors stormed a government-owned rice warehouse seeking food supplies.

The Philippines National Food Authority said police and soldiers stood by helpless as people streamed into the warehouse in Alangalang, Leyte province – an area where hunger and desperation are running high after Haiyan made landfall early on Friday morning, ravaging vast swaths of Leyte and Samar islands. The security forces could only watch as more than 100,000 sacks of rice were carried away.

The eight were crushed to death when a wall in the warehouse collapsed, spokesman Rex Estoperez told the Associated Press. Other rice warehouses were dotted around the region, he said, refusing to give their locations for security reasons.

The Philippines government has come under fire for failing to deliver aid adequately or quickly enough, with growing frustration in the hardest hit areas, such as Tacloban, the capital of Leyte province where dead bodies have piled up on the streets and residents have resorted to looting to find food.

A military official told the Guardian on Wednesday that the government was aiming to double its relief efforts within the next two days. Attempts to provide help were buoyed by the expected arrival of two extra US military C-130 planes and one additional Australian air force plane.

Three relief distribution points were being set up in the Leyte island towns of Tacloban, Guiuan and Ormoc, the official said, with the main aid effort operating out of neighbouring Cebu instead of Manila, the capital, which is 360 miles to the north.

More than 10,000 people are feared to have been killed in the Philippines due to Haiyan, most of them in Leyte province, with aid workers suggesting that number may rise significantly. As many as 29 municipalities have still not been reached due to impassable roads and downed telecommunications.

President Benigno Aquino III said on Tuesday that he believed the number killed to be far lower – around 2,500 – and told CNN that the 10,000 figure may have come from an "emotional" official, with government figures alleging that the death toll stands at 2,275. The UN has said more than 670,000 people have been displaced and a total of 11.3 million people directly affected by the super storm.

International relief efforts intensified with the launch of a UN appeal and the dispatch of American, British and Japanese troops to the affected regions. But minimal amounts of aid have reached the worst‑hit areas.

More than 3,000 people surged on to the tarmac of Tacloban airport on Tuesday morning in the hope of flying out on the two Philippine air force planes that had just arrived.

Babies and sick or elderly people were given priority but only a few hundred were able to leave. Others were held back by soldiers and police. Many had walked for hours and camped at the base overnight.

"I was pleading with the soldiers. I was kneeling and begging because I have diabetes," said Helen Cordial as she lay on a stretcher, shaking. "Do they want me to die in this airport? They are stone-hearted," she told the Associated Press.

Dean Smith, an Australian who has been living with his family near Palo, Leyte province, for the last five years, told the Guardian that he waited eight hours to be able to get one of the first commercial flights out of Tacloban to Cebu. On the way to the airport he said he saw "horrifying things that I know I have seen but my brain hasn't processed yet".

He described scenes of chaos in the city centre, where police were stealing money from the local cashpoints, people in cars were refusing to drive the injured to get help, and the bloated body of a man floating in dirty water was being gnawed at by a dog.

"What people have gone through, what they have seen – there is going to be a lot of post-traumatic stress after this event I assure you," he said shakily. "No one has ever seen anything like this."

Having arrived on Tuesday in Cebu, Smith was planning to stock up on food, medicine and water and take it back to his Palo home, where his wife, six children, a 92-year-old grandmother and a pregnant nanny were all desperately awaiting supplies. He departed for Tacloban early on Wednesday morning.

Domestic and international relief efforts were being hampered by wet weather, poor communications and damaged infrastructure, with aircraft only able to land in Tacloban during daylight hours because the air control tower had been destroyed by Haiyan. Unsubstantiated reports of aid convoys being attacked by hungry victims circulated, with the Telegraph reporting that communist rebels had been killed whilst trying to intercept a Red Cross convoy destined for the island of Samar.

Still, Corizon Soliman, secretary of the Philippine department of social welfare and development, said aid had so far reached a third of the city's 45,000 families.

However armed forces spokesman Ramon Zagala told the BBC that relief workers were struggling to deliver aid for a number of reasons.

"The area is very vast and the number of helicopters – although we have a lot of helicopters at the moment – it's really a challenge for us to bring [aid] to all the places and [bring] the number of goods that are needed."

The BBC quoted a Leyte official as saying that although relief goods like medicine and equipment were arriving into the province "it's just not reaching the people affected".

The UN released $25m (£15.7m) in emergency funds for shelter materials and household items, and for assistance with emergency health services, safe water supplies and sanitation.

The UN aid chief, Valerie Amos, launched an appeal for $300m as she arrived in Manila. "We have deployed specialist teams, vital logistics support and dispatched critical supplies but we have to do more and faster," she said.

The US, Britain, Japan, Australia and other nations have pledged tens of millions of dollars in immediate aid, and some businesses have also offered help: banking group HSBC announced a $1m (£630,000) cash donation.

In Tacloban shops were stripped of food and water by hungry residents. While some tents had arrived, the widespread damage left many people sleeping in the ruins of their homes or under shredded trees.

Military doctors at a makeshift clinic at the airport said they had treated about 1,000 people for cuts, bruises and deep wounds but did not have enough medical supplies.

"It's overwhelming," said Antonio Tamayo, an air force captain. "We need more medicine. We can't give anti-tetanus vaccine shots because we have none."

The typhoon flattened Basey, a seaside town in Samar province about six miles across a bay from Tacloban. About 2,000 people were missing there, its governor said. Rescue and relief workers were yet to reach many of the more remote areas.

"There are hundreds of other towns and villages stretched over thousands of kilometres that were in the path of the typhoon and with which all communication has been cut," said Natasha Reyes, emergency co-ordinator in the Philippines at Médecins Sans Frontières. "No one knows what the situation is like in these more rural and remote places, and it's going to be some time before we have a full picture."

Damage to communications left the armed forces struggling to reach local authorities and many officials were dead, missing or trying to protect their own families.

"Basically the only branch of government that is working here is the military," Ruben Guinolbay, a Philippine army captain, told Reuters in Tacloban. "That is not good. We are not supposed to take over government."

The interior secretary, Manuel Roxas, said on Tuesday that only 20 of Tacloban's 293 police had arrived for work. But he added: "Today we have stabilised the situation. There are no longer reports of looting. The food supply is coming in. Up to 50,000 food packs are coming in every day, with each pack able to feed up to a family of five for three days."

A team of British medical experts and the first consignment of aid from the UK was leaving for the Philippines, David Cameron said on Tuesday.

The UK surgical team, led by Anthony Redmond, Manchester University professor of international emergency medicine, includes three emergency physicians, two orthopaedic surgeons, a plastic surgeon, two accident and emergency nurses, a theatre nurse, two anaesthetists and one specialist physiotherapist.

The USS George Washington aircraft carrier, transporting about 5,000 sailors and more than 80 aircraft, plus four other US navy ships, should arrive in two to three days, the Pentagon said.

Britain's HMS Daring, a warship with equipment to make drinking water from seawater, and a military transport aircraft should arrive around the same time.

Japan is sending a team of 40 from its self-defence force.

Aquino has declared a state of national calamity, allowing the central government to release emergency funds more quickly and impose price controls.

Initial estimates of the cost of the damage vary widely, with a report from German-based CEDIM Forensic Disaster Analysis putting the total at anywhere from $8bn to $19bn.