After five months of secretive deliberations, the sultan of Yogyakarta has chosen the new spiritual guardian of Indonesia's seething Mount Merapi volcano, a palace official said Tuesday.

The job of listening to the volcano's every rumble and soothing its fearsome temper will be passed to Asihono, the son of the late guardian, Grandfather Marijan, who died on its slopes during a massive eruption in October.

"As the gatekeeper of Mount Merapi, besides maintaining the tradition, he should also be able to collaborate with volcanology officials," palace official Gusti Joyokusumo said.

"There should be good communication between them so the people can benefit."

The 44-year-old will be expected to lead traditional rituals to appease the 2,914-metre (9,616-foot) volcano's spirits, in honour of a 17th-century pact between the House of Yogyakarta and the mythical Queen of the Southern Sea.

Locals believe that in return for peace and protection, the original sultan and his nine descendants had to wed the queen and present annual offerings to the four abodes of spirits allied to the palace.

These are Merapi to the north, Parangkusumo beach to the south, Mount Lawu to the east and the sacred pond of Dlepih Kahyangan to the west.

In Javanese mysticism, the palace in Yogyakarta occupies a central position, while the spirits residing in the four corners protect the sultan and his people.

Merapi, whose name translates as "Mountain of Fire", killed more than 300 people and displaced close to 400,000 when it erupted last year.

Aged in his 70s, Marijan refused to evacuate his house beneath the smoking crater and died in the the first blasts of searing heat clouds.

His body was found covered in ash and reportedly in a position of prayer, suggesting the old gatekeeper had struggled to the end to soothe the violent energies in the mountain's core.

A search and rescue worker who was among the last to see Marijan alive told AFP shortly after his death that the old man had stayed true to his duty.

"I'm so used to being at home, it's better for me to just stay here and pray," the rescuer quoted him as saying.