Australians traveling to Bali are being warned about an outbreak of rabies.

The Indonesian island was considered to be rabies free until the disease was diagnosed last week in two dogs in Kuta, a beach frequented by Australians. Rabies affects the brain and is almost always fatal without treatment. The usual incubation period for the disease is three to eight weeks.

The NT Department of Health and Families has issued a statement warning people visiting the island to avoid dogs, cats and monkeys.

"At the moment, there is no indication that the disease has spread to animals other than dogs," said the acting director of the NT's Centre for Disease Control, Peter Markey.

"However, any animal should be considered to pose a potential risk."

Dr Markey said Bali authorities had taken steps to control the situation, implementing a program of culling and vaccinating dogs and people in the affected villages. He said anyone who had returned from Bali since August with bites or scratches from an animal should seek medical advice.

"If you're planning on visiting Bali, then avoid direct contact with all dogs and cats, monkeys and other animals," Dr Markey said. "If you are bitten or scratched by an animal, seek medical attention immediately."

People suspected to have been exposed to rabies should receive rabies immunoglobulin (RIG) and a rabies vaccination as soon as possible, Dr Markey said.