Up to 4,000 people are still trapped under rubble following Wednesday's powerful earthquake off the Indonesian island of Sumatra, officials say.
The United Nations says at least 1,100 people have died and the chances of finding survivors are growing slimmer.
Indonesia is appealing for more foreign aid, as a huge aid effort gains momentum. However, three days after the disaster struck rescuers are only starting to reach some stricken communities.
Fresh aid supplies are due to arrive at Jakarta's main airport for transfer to the disaster area, 915km northwest of the capital. Aid is also being shipped from Jakarta's port of Tanjung Priok.
The stench of decomposing bodies has now started to pervade wrecked buildings, including schools and hotels, where exhausted police and soldiers are still scrambling to find people clinging to life under the rubble.
Indonesia's health minister has speculated the final death toll could be as high as 4,000.
That figure is borne out by the head of the Indonesia delegation of the International Red Cross, Bob McKerrow. He says his estimate is 4,000, based on his tour of the city of Padang and surrounding countryside.
Indonesian President Susilo Bambang Yudhoyono toured the disaster area and said $US10m in relief would be put to work fast.
Foreign rescue teams arrive
Rescue teams from Australia, Russia, Japan, the UK and the European Union are among those sending emergency supplies, medics and rescue teams, in a last push to save lives.
Some rescuers are focused on a hotel where as many as eight people may still be alive. Voices were heard from under the rubble, and a newly-arrived Swiss rescue team said its sophisticated audio equipment had picked up frantic knocking sounds.
Those trapped are believed to be on the 6th floor and rescuers are building a tunnel into the rubble to try to reach them.
A woman was pulled alive from the wreckage of a school on Friday more than 40 hours after she was trapped.
A tunnel had to be built into the mound of debris to reach her. The rescue was a boost to emergency workers.
At Padang's main M. Djamil hospital, a constant stream of injured residents were being dropped off at hastily erected tents where doctors worked frantically to treat victims.
Rescue and aid efforts have been hampered by power blackouts and a shortage of heavy equipment and aid organisation World Vision says fewer people are being pulled out alive from under the rubble.
Jakarta-based operations director Amelia Merrick told Radio New Zealand's Checkpoint programme on Friday that rescue workers are now racing against time.
United Nations humanitarian chief John Holmes says he fears the number of casualties will rise as more information becomes available.
Rural districts cut off
Many districts remain inaccessible to emergency services, power has been cut and telephone connections are patchy, making it hard for officials to work out the extent of destruction and loss of life.
Indonesian Red Cross chief Marie Muhammad says there are still many roads cut off because of landslides.
Food shortages are being reported in areas where the earthquake has damaged roads, while people who lost their homes are said to be sleeping in the streets.
Aid workers and reporters say that in rural areas thousands more buildings have been destroyed and whole villages flattened.
"From the aerial assessments carried out (on Friday), the feedback is, yes Padang city and environs are bad, but once you go outside into the surrounding rural areas, the situation is very seriously grave," said International Red Cross coordinator Christine South, quoted by AFP news agency.
There was still no information for some areas including Mentawai Island, 57km from the coast, she said.
An AP reporter says parts of Pariaman district, to the north of Padang, have virtually no buildings left standing and has received no outside help.
Dozens of aftershocks have followed the quake, including a major one on Thursday which the US Geological Survey measured at 6.8 and said struck on land 225km southeast of Padang.
New Zealand's Ministry of Foreign Affairs and Trade said it has contacted most of the 30 people and dependents who are in Indonesia. There are no reports of any New Zealanders injured or killed.