"If we do not do anything, the lights will go out for the fireflies by the end of the year," said Elizabeth Wong, who heads tourism and environmental affairs in the state of Selangor, which surrounds Malaysia's capital.

Wong said environmental groups had alerted the state government to the "impending destruction" of the riverside firefly colony, which lies about 90 minutes' drive from Kuala Lumpur.

Tourists flock to the area to watch the fireflies, which cluster in riverside trees and produce a magical light display as males and females communicate.

Tour operators say the number of insects has fallen sharply because of development in the area.

Wong said that despite the region's being declared a firefly sanctuary, almost 95 acres (38 hectares) of land along the Selangor river had been cleared of the trees in which fireflies live.

"Four out of the seven critical spots which the fireflies depend on has been cleared bare of vegetation. This is the place where they get their food and lay their eggs to sustain their three-month life cycle," she told AFP.

Wong said felling in the area, which is destined to become palm oil plantations, had also polluted the river.

The Selangor state government, won in elections last year by the Pakatan Rakyat opposition alliance, is to impose an immediate stop-work order along the river to save the insects, she said.

"We will also begin immediate planting of sagu, berembang, nipah and rembau (trees) which are frequented by the fireflies, to boost their population," Wong said.

"The numbers of fireflies have gone down drastically. They are dying out. We are not going to wait until there are just one or two fireflies before we act. We need to save the insects before it is too late."

Bert Che, senior executive with Firefly Park Resort in Kuala Selangor, which organises the river tours, called for swift action to protect the fireflies.

"I hope everyone will treasure our fireflies. If we don't, our next generation will not be able to see the insects," she said.