At least six alleged tiger poachers were killed today during a gunfight with Bangladesh police in Sundarbans, the world's largest mangrove forest stretching both Bangladesh and Indian coastlines.

"Police initially detained six of the poachers and asked them to lead us (police) to their hideouts inside the forest... their associates attacked us and we retaliated when the six were killed in crossfire," a police officer said.

The poachers were arrested from different parts of Koyra area of the forest early in the morning while they caught in the line of fire and died instantly during the shootouts in the afternoon at Mandarbari of the Sundarbans, he said.

Five policemen were also injured in the gunfight, the officer said, adding that four guns, three pistols and three pieces of tiger hide were also seized from the scene.

The gunfight was reported two weeks after the census was released revealing that the number of the Sundarban's famous Bengal Tiger population was far fewer than it was previously thought, sparking an uproar among environmentalists, who demanded intensified anti-poaching campaigns.

During the previous census in 2004, some 440 tigers were recorded in the Sundarbans, one of the last remaining habitats for the big cats.

Experts, however, questioned the accuracy of the previous census when pugmarks were recorded but the hidden cameras used during the last survey gave a more accurate result.

About 74 tigers have previously been counted on the Indian side of the Sundarbans, which makes up nearly 40 per cent of the forest straddling both countries over 10,000 sq km.