China ramped up efforts on Saturday to stave off disease for millions of earthquake victims, as more miracle rescues amid the rubble offered hope in an increasingly desperate battle to save lives.

Five days after the enormous earthquake that the government estimates killed more than 50,000 people, there were rising concerns over potential disease outbreaks among the nearly five million survivors who have lost their homes.

"Combating epidemics is the most urgent and the biggest task facing us right now," Wei Chao'an, vice minister of agriculture, told reporters in Beijing.

The death toll from the 7.9-magnitude quake continued to climb as authorities cleared their way through pulverised towns and gained better access to isolated areas -- gaining a clearer picture of the full scale of the horror.

The government raised the confirmed death toll by more than 6,000 to 28,881. But many expect the eventual figure could surpass even the government's estimate of more than 50,000.

Entire towns in mountainous Sichuan province were flattened in Monday's quake, with the main zone of destruction spreading across 100,000 square kilometres (40,000 square miles) -- an area three times the size of Belgium.

The tremor, which could be felt as far away as Bangkok, saw mountainsides in Sichuan sheared off, roads split in two and countless thousands of buildings toppled or in danger of collapse.

Since the quake, the most pressing priority has been to rescue those trapped amid the mass of twisted metal and concrete. Five more people were pulled out of the rubble on Saturday.

After 124 hours, a 31-year-old woman was rescued from the rubble of a building in Deyang city, while around the same time a 33-year-old worker was hauled out of a phosphorous mine in Shifang city, Xinhua news agency reported.

A third man was also saved about the same time. The three were the people known to have survived the longest in the debris since Monday's quake.

Xinhua had earlier reported that a German had also been pulled from the rubble. But it later revised the story, saying that 62-year-old climber Brakus Bogdan was unhurt and had spent five days in a remote quake-hit village.

The rescues on Saturday defied the warnings of experts that chances of survival were extremely small after 72 hours.

"As long as people are waiting to be rescued it's possible," said Bob Tan, part of a 55-strong Singaporean team that arrived in the mountain-perched town of Hongbai.

"Miracles do happen, that's why we never give up hope," he said.

Residents of Hongbai said that up to 900 of the town's 10,000 people died, 200 of them children.

China initially rebuffed offers of help from foreign rescue experts, but teams from Japan, Russia, Singapore and South Korea have now begun operating in the disaster zone.

Teams have also headed in from Taiwan -- which China considers to be part of its territory -- and Hong Kong.

The international experts have brought in sniffer dogs, fibre-optic scopes, life detector systems and hydraulic cutters and spreaders.

"Where there is a beam of hope, we will spare no efforts to save the trapped," Chinese Premier Wen Jiabao said Friday.

As the rescue effort pressed on, other authorities focused on supplying fresh drinking water and improving sanitary conditions for the 4.8 million people who lost their homes and are living in tent cities or in the open.

China's health ministry said it could not rule out major epidemics, since the rudimentary sanitation and uncertain access to safe water and food supplies were a potential lethal breeding ground for infectious diseases.

China's top veterinarian, Li Jingxing, said the rotting carcasses of 12.5 million livestock and poultry killed by the quake were also a major risk.

"For these carcasses we are adopting measures such as deep burial to ensure that no epidemics are caused," said Li, who heads the veterinary department at the agriculture ministry.

Huge water purification machines capable of providing for up to 10,000 people a day were being taken into some of the most remote areas of Sichuan province, while authorities were frantically distributing portable toilets.

In Shifang city, where more than 2,500 people have been confirmed killed and thousands more remain missing, leaflets were being given to advise on hygiene and how to prevent disease.

PHOTO CAPTION:

A crowd watches a body pulled out of the rubble.

AFP