Seven Komodo dragons have hatched under a breeding programme at an Indonesian zoo, an official said Wednesday, a success story that raises hope for the endangered lizard.

Twenty-one eggs from two Komodo dragons were placed in incubation at the Surabaya Zoo in eastern Java, the first batch in September and the second in October, with seven hatching on March 10.

"Some of the eggs from the first Komodo did not hatch, which is normal. We're hoping for another seven or eight from the second clutch, which are due to hatch around April or May," zoo spokesman Anthan Warsito told AFP on Wednesday.

He said the hatchlings were the result of a breeding programme that begins with incubation and involves protecting the young from predatory cannibalistic adult dragons as well as placing microchips in the babies to monitor their progress.

Komodo dragons, the world's largest lizards, can reach around three metres (10 feet) in length and 70 kilograms (154 pounds) in weight and are endemic to a cluster of islands in eastern Indonesia.

They are also popular at zoo exhibits around the world.

The species is considered vulnerable, with around 5,000 left in the wild.

Although deadly attacks are rare, several Komodo dragons have clashed with humans in recent years, the latest victim an Indonesian tour guide who was in February bitten on the calf in the Komodo National Park.