Bangladesh said on Monday that nine forest officials had been suspended for "gross negligence" after three Bengal tiger cubs were found in a house in Dhaka where they were being kept by smugglers.

Bangladesh's elite Rapid Action Battalion (RAB) rescued the two-month-old cubs in June after a tip-off that the endangered animals from the Sundarbans mangrove forest were in cages at the house ready to be sold.

The raid raised alarm over the safety of about 400 tigers living in the Bangladeshi part of the 10,000-square-kilometre (4,000-square-mile) coastal forest straddling the border with India.

Sundarbans forest chief Jahiruddin Ahmed told AFP that the nine officials, included a deputy ranger, were suspended after failing to discharge their duties properly.

"There was gross negligence in their part to protect the cubs," he said, adding that honey collectors who had permits to enter the dense and marshy forest smuggled the cubs out and sold them to the smugglers.

There were just 440 Bengal tigers left in Bangladesh when the last census was held in 2004, with about 1,700 in India and a worldwide total of less than 2,500, according to the International Union for Conservation of Nature (IUCN).

Police said they believed an organised racket was behind the tiger trafficking as several empty cages were found in the house, indicating that it was used as a transit hub for the illegal wildlife trade.

Officers said they were uncertain whether the tigers were destined for private zoos, or whether their bones and other body parts were wanted for use in traditional medicine.

One man who was arrested alleged that government conservationists were involved, but a probe cleared them of any wrongdoing.

The man and his mother were both jailed for smuggling for two years, while seven others are on bail awaiting trial.

In 2010, the Bangladesh government enacted new laws with stringent punishments to protect wildlife, including the Bengal tiger, but poaching remains rampant.