A critically endangered Sumatran tiger was shot dead on Saturday while another is still on the loose after they escaped from a zoo on Borneo island, leaving a zookeeper dead, an official said.

The tigers, both female and about 18 months old, escaped from Sinka Zoo in the town of Singkawang, West Kalimantan late Friday after days of torrential rain caused a landslide and opened a tunnel allowing their exit. 

A 47-year-old zookeeper was found dead with scratches and bite wounds on his body.

Authorities also found dead a cassowary, ostrich and monkey near the tiger cage. 

Police and conservation officials were immediately dispatched to search for the tigers. 

Nearby tourism attractions were ordered to close and locals were told to stay at home while police searched for the animals. 

"We tried with a tranquilliser gun first but it didn't work, so we were forced to shoot the tiger because it was already behaving very aggressively," Sadtata Noor Adirahmanta, the head of a local conservation agency, told AFP.

"We were afraid it would escape to the nearest neighbourhood. Although we tried our best to catch it alive, our priority is humans' safety," he added. 

Authorities are still looking for the other tiger in the jungle surrounding the zoo.

A cage with animal prey inside has been prepared in hope the escaped tiger will return to the zoo at her feeding time.

Sumatran tigers are considered critically endangered by the International Union for Conservation of Nature, with fewer than 400 believed to remain in the wild.

Tiger parts are widely used in traditional medicine -- particularly in China -- despite overwhelming scientific evidence they have no beneficial value.