Philippine rescuers dug through rock and mud Friday looking for people feared buried by a deadly landslide at a remote gold mining community, as officials vowed to shut down unsafe mine sites.

At least 25 people were killed on Mindanao island before dawn on Thursday when a rock and mud avalanche buried a mountain settlement of gold prospectors who had refused to leave an area declared too dangerous for habitation.

However, the national government began to back away from the previous official figure of 150 people missing, saying only eight of them are known by name and there were no reliable census figures at the gold rush site.

"I think that is exaggerated," civil defence chief Benito Ramos told AFP, adding the original estimate was given by local officials in the area who extrapolated the figure from the number of buried shanties.

"It would be hard to even give an estimate," he said.

Interior Secretary Jesse Robredo flew to the disaster site near Pantukan town on Friday and also downplayed the initial estimate of the missing.

"That might not be a very accurate number," said Robredo, interviewed over ABS-CBN television in Pantukan.

He said 80 percent of the population were recent migrants chasing instant riches from high gold prices.

"Hopefully the search team there will be able to get it done in 48 hours," Robredo added.

Pantukan's civil defence office said the toll now stood at 25 dead and eight missing, while 16 were rescued and treated at Mindanao hospitals.

Meanwhile, Robredo announced the government would shut down up to 500 small-scale mines that dot the mountainsides around Pantukan and relocate the affected miners and their families, who will be given state financial aid.

About a thousand mine tunnels operate in the area, he said.

"Probably half of these are without permits, so we (he and the local officials) agreed that all the illegal tunnels will be closed down."

Their shanties would be demolished, while the government will force the remaining miners to mill their ore at three centralised areas that will be put up closer to downtown within three months, Robredo added.

More rescuers were sent to the site Friday to help more than a hundred police and military personnel there, said local military spokesman Lieutenant-Colonel Lyndon Paniza.

"We're not losing hope in our search for survivors. We will not shift to (corpse) retrieval mode until 72 hours had passed," he told AFP.

Rescuers are pushing tubes into the mouths of mine shafts that tunnel into the mountainside in the hope that some trapped miners could still be alive inside but so far there had been no signs of life, he conceded.

The mountainous region has drawn gold prospectors for years despite frequent, deadly landslides.

Their largely unregulated tunnelling have made the mountainside unstable, government experts say, and heavy rains since last month had saturated the earth on top, helping to trigger the earthfall.