The female tiger, aged between two-three years, was found in South Aceh district on Monday with injuries caused by a snare, said Agus Arianto, the head of the provincial government's Nature Conservation Agency.

"A necropsy indicates it died of poisoning caused by an agricultural insecticide," he said on Wednesday.

It was not clear if the tiger was deliberately poisoned.

Last month, another Sumatran tiger died after it ate a sheep laced with rat poison in neighbouring North Sumatra province.

In June, police in Aceh also arrested four people for allegedly killing a tiger with a trap and selling its hide, skull and fangs for 100 million rupiah $A10,154.

Conservationists said the coronavirus pandemic had led to increased poaching in the forests on Sumatra island, as locals turn to hunting to make ends meet.

The Sumatran tiger is the only tiger subspecies left in Indonesia, after the tigers on the islands of Java and Bali became extinct years ago.

There are only about 400 Sumatran tigers left in the wild, and their population is dwindling due to poaching and loss of natural habitat caused by rapid deforestation for palm oil plantations, conservationists warn.

Australian Associated Press