Authorities in Bali are warning about the outbreak of a rare and deadly disease.

Japanese Encephalitis has emerged in Indonesia, and the tourist hotspot has the highest number of cases.

The disease can be spread from human to human via mosquito bites, and bats, pigs and poultry can also carry the disease.

Japanese encephalitis kills about a quarter of its victims. (Supplied)

Australian visitors to Bali are warned to stay in air-conditioned or screened rooms, and to avoid dirtier rural areas.

Japanese Encephelatis is a brain infection and can be deadly.

One in four cases prove to be fatal.

Symptoms can take up to 15 days to become noticeable, and include fever, headache, neck stiffness, tremors, convulsions in children and even paralysis.