At least five people were killed and several others believed to be missing after a landslide on a mountainous road in the Philippines Monday, the military said, as heavy rain hampered rescue efforts.

The relentless rain caused the landslide on the undeveloped southern island of Mindanao, burying an unknown number of people, said Lieutenant Colonel Jose Maria Cuerpo, commander of military forces assisting at the scene.

"My people, they counted five dead bodies and three injured," Cuerpo told AFP by telephone.

He said local government officials estimated that 15 people or more might still be buried in the rubble but this could not be verified.

"We are hoping and praying that it will be a smaller number of missing," Cuerpo said.

Troops and local government personnel had initially dug through the rubble with hand tools. Heavy equipment later arrived at the mountain road but heavy rain made it too dangerous to dig, said the military officer.

"We have stopped because it is raining very hard now. The mountainside is still rather soft, so we stay cautious for now," Cuerpo said.

Officials earlier said the landslide had buried at least five motorcycles.

In the southern Philippines, motorcycles are often used overloaded with passengers. Modified motorcycles with extended rear benches can carry as many as five or six people.