At least six have died people in Indonesia after a series of volcanic eruptions on the remote island of Flores.

The eruption at Mount Lewotobi Laki Laki about midnight on Monday spewed thick brownish ash as high as 2,000 metres into the air and hot ashes hit a nearby village, burning down several houses including a convent of Catholic nuns, said Firman Yosef, an official at the Mount Lewotobi Laki Laki monitoring post.

Indonesia's Disaster Management Agency lowered the known death toll from an earlier report of nine, saying it had received updated information from local authorities.

It said that information was still being collected about the extent of casualties and damage, as local media reports said more people were buried in collapsed houses.