Authorities are searching for two miners trapped and feared dead in an illegal tunnel in the Philippines.

Rodilo Campanya, 36, and Henry Rabino, 50, descended down the 80ft-deep hole to search for precious metals, but never returned home in Panabo City, Davao del Norte province, on March 31.

Firefighters and police launched a search when locals reported hearing a loud explosion from the tunnel.

Michael Angelo Resueno, Panabo City Information Officer, said in an April 4 press conference: 'There was a suspected flammable substance. And possibly, the two victims who brought with them a hammer and nails which may have triggered the explosion.'

Officials have not yet found the men's bodies as the tunnel was filled with water and flammable hydrogen sulfide.

The local government said the excavation site owned by a corporation was unauthorised by the Department of Environment and Natural Resources.

Authorities said they were investigating the illegal mine and have extended assistance to the missing villagers' families.