More than 80 environment ministers gathered in India on Thursday inched towards a global deal to increase the amount of cash set aside to protect the natural environment, delegates told AFP.

Discussions ahead of the end Friday of the UN Convention on Biological Diversity (CBD) conference in Hyderabad were focused on how to double spending in the developing world by 2015 or 2020 compared with the average for 2006-2010.

The money, both public and private, is to be spent on measures such as creating nature or ocean reserves or funding environmental research in a bid to arrest the depletion of the plants and animals on which humans depend.

"It's a game of brinkmanship, but we are moving towards an agreement nonetheless," Sandrine Belier, one of three members of the European Parliament attending the conference, told AFP.

Current conservation spending is estimated at about $10 billion per year.

"Doubling the investment, it's reasonable," said Lasse Gustavsson, a conservation expert at nature charity WWF.

"In the difficult economic circumstances in Europe, it's unlikely that we'll have a big financial deal tomorrow," he added, however.

Underlining this, British Environment Minister Richard Benyon told AFP that London was happy to contribute but wanted to be sure "that we are not leaving ourselves open to putting greater burden on our taxpayers".

The conference was also expected to reach agreement on scientific research that identifies areas of the west Pacific as well as Caribbean and Mediterranean Seas as being in danger and in need of protection.

Under the Millennium Development Goals, countries pledged to achieve "a significant reduction" in the rate of biodiversity loss by 2010, but they have failed to achieve the target.

An island-dwelling cockroach and a tiny snail were declared extinct on Wednesday while 400 plants and animals were added to a "Red List" of threatened species compiled by The International Union for Conservation of Nature.

An estimated 20,219 species are at risk of dying out.

Seeking to counter the crisis, the last CBD conference in Nagoya, Japan, adopted a 20-point plan in 2010 to turn back biodiversity loss by 2020.

The so-called Aichi Biodiversity Targets include halving the rate of habitat loss, expanding water and land areas under conservation, preventing the extinction of species currently on the threatened list, and restoring at least 15 percent of degraded ecosystems.