A critically endangered Sumatran tiger at a notorious Indonesian zoo where hundreds of animals have died in recent years is emaciated and on the brink of death, an official said on Wednesday.

Melani, a 15-year-old female, has been suffering from a serious digestive disorder for the past five years due to a diet of tainted chicken which has pushed her weight down from 80 to 60 kilograms (176 to 132 pounds).

"She is a hopeless case," said Tony Sumampau, chairman of Indonesia's zoo association who oversees Surabaya Zoo, where the tiger lives.

"Her days are numbered, she could die any time. She's in a pitiful state and losing more and more weight."

Sumampau added that Melani was unable to digest any food, and that the zoo might put her down.

From when she was born, she had been fed a diet of chicken containing chemicals including pesticide, he said, adding the supplier was changed three years ago but by then it was too late.

Earlier this month another Sumatran tiger, a 13-year-old male, died from a similar digestive illness, he said.

Many other animals have died due to neglect and management in-fighting in recent years at Surabaya Zoo. Those still alive languish in cramped, dirty cages and suffer from illnesses including pneumonia and diarrhoea.

Fewer than 400 Sumatran tigers are left in the wild, conservationists say.