Thirteen countries with wild tiger populations agreed Tuesday to take part in a global count to establish how many of the critically endangered big cats are left and improve policies to protect them.

Experts say that although the tiger population is thought to have remained stable over the last four years, a lack of accurate numbers is hindering effective policies.

The pledge came at a global conference in the Bangladeshi capital Dhaka where more than 140 people have converged for three days to discuss actions to save the tiger.

"We really need science-based data on the number of tigers," said John Seidensticker of the Smithsonian Conservation Biology Institute in Washington.

The count is due to be completed within two years and will replace data Seidensticker said was based mostly on "guesstimates".

The world's wild tiger population fell to little over 3,200 in 2010 from 100,000 only a century ago and the International Union for the Conservation of Nature has listed the animal as critically endangered.

Poaching, encroachment on its habitat and the illegal wildlife trade are blamed for the declining numbers.

In 2010 the 13 countries with tiger populations -- Bangladesh, Bhutan, China, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Russia, Thailand and Vietnam -- launched a plan to double their numbers by 2022.

Officials at Tuesday's conference said populations had risen in major "tiger range" nations such as India, Nepal and Russia.

But poaching continues to be a major problem. Statistics from TRAFFIC, the wildlife trade monitoring network, show that at least 1,590 tigers -- an average of two a week -- were seized between January 2000 and April 2014.

"We recognise that poaching is still the number one threat to tigers. It's happening all over the tiger ranges. But we are still not really seeing strong commitment by the governments put in place against poaching," said Mike Baltzer of conservation group WWF.

Seidensticker said some concerns also stemmed from recent findings that "forested habitat within protected areas and tiger conservation landscape have declined over the last 10 years".

Bangladesh has come under fire for setting up a giant coal-fired power plant on the edge of the Sundarbans mangrove forest, home to one of the largest tiger populations.

Experts fear the 1,320-megawatt power plant being built just 14 kilometres (nine miles) from the Sundarbans will pollute the water of the world's largest mangrove forest, jeopardising its delicate biodiversity and threatening the tiger population.

"The impact will be disastrous. It will break up the Sundarbans into isolated parts, affecting tiger breeding," said Y.V. Jhala of the Wildlife Institute of India.