Thousands of soldiers in the quake-hit Philippines Tuesday scoured villages buried under landslides, but authorities said hopes of finding dozens of missing people alive were dim.

Two days after a 6.7 magnitude quake flattened homes, destroyed bridges and triggered deadly landslides in the central island of Negros, rescuers had yet to find anyone alive among at least 92 people reported missing.

"Rescue teams have so far not seen or heard any signs of life underneath," Ernesto Reyes, mayor of the city of Guihulngan on Negros island where 29 people from a small mountain community were believed buried by a landslide, told AFP.

"None of our missing have so far been retrieved."

At least 48 people were confirmed to have died in Negros, with another 92 missing, regional military commander Colonel Francisco Patrimonio said on Tuesday.

In Manila, the national government's disaster office said on Wednesday its death toll was 22, with 71 missing, but acknowledged it had not yet been able to verify reports from authorities in Negros.

Reyes said the mountain community in Guihulngan was buried under about 10 metres (30 feet) of debris, with rescue efforts painfully slow because people had only picks, shovels and their bare hands to claw through the dirt.

Roads and bridges to Guihulngan, a coastal city of about 100,000 flanked by mountains, were badly damaged in the quake, meaning earth movers and supplies for survivors could not be quickly deployed to the area, he said.

"Our immediate concern now is how to serve the living -- we don't have enough food, there is no electricity and water," Reyes said.

"We are appealing for help from everyone."

The other missing people were reported in the nearby farming town of La Libertad, where a cluster of hillside homes were also crushed by a landslide, according to Negros Oriental province governor Roel Degamo.

"We are in a state of shock, and all we can do now for those still missing is to pray," Degamo said.

He said soldiers and rescuers raced against time Tuesday to find a young woman who had sent a mobile phone text message to her relatives that she was pinned down, but alive.

The dramatic search, however, ended in tears hours later.

"She was found dead and still clutching her cell phone," Degamo told AFP, declining to give further details about the victim in deference to her grieving family.

Civil Defense Office chief Benito Ramos said five military battalions, or about 2,000 troops, had been deployed to the devastated zones and were helping local rescue units.

"We are racing against time, and hoping against hope that maybe, just maybe some of them might still be alive," he said.

However, he said the military had not yet been able to get heavy equipment into the landslide-devastated communities because of the damaged roads.

President Benigno Aquino was expected to fly into the disaster zone Wednesday to personally check on the search and rescue operations.