Jakarta - The number of critically endangered Sumatran tigers at an Indonesian national park has increased over the past few years thanks to a successful campaign against poaching, a conservationist said Tuesday.

The result of a 20-month monitoring programme showed that the population of Sumatran tigers at the Bukit Tiga Puluh National Park in Riau province had risen to 43 from 35 in 2003, said Muhammad Yunus, coordinator of the park's Sumatran Tiger Conservation Programme.

"The result is beyond our expectations," Yunus was quoted as saying by the state-run Antara news agency.

Twelve cameras equipped with infrared triggers were installed at the park to monitor the species' population, he said.

Yunus attributed the increase to the success of the campaign against tiger poaching.

"Before, tiger hunting by outsiders who employed local people was rampant," he said.

A female tiger can give birth to up to five cubs but only two of them are likely to survive, the conservationist said.

The conservation group WWF said there are fewer than 400 Sumatran tigers in the wild and they can only be found on Indonesia's Sumatra island.

WWF said tigers were once widespread on the Indonesian islands of Bali and Java but these two subspecies became extinct in the
20th century.

Logging and rampant poaching are driving the Sumatran tiger to extinction, it said. (dpa)