The race to protect the world's rhino, elephant and shark populations from the bloody trade in animal body parts will be at the heart of key endangered species talks in Bangkok from Sunday.

In its first meeting since 2010, delegates from the Convention on International Trade in Endangered Species (CITES) will meet to assess levels of protection for animals and plants, as wildlife organisations warn of an increasingly desperate fight against poaching networks.

Rhinos and elephants are already listed as protected species and their international trade is banned, with some exceptions. But poaching has reached alarming levels in recent years, leading to calls for stricter new measures.

Host nation Thailand itself looks set to be at the heart of discussions.

Seen as a hub for traffickers of all endangered species, the kingdom has been singled out for allowing the legal sale of Asian elephant ivory in its territory.

Conservationists say criminals exploit this trade to sell illicit stocks of African ivory -- which is practically impossible to differentiate from that of Asian elephants.

The WWF has launched a petition to ban all trade in ivory in the kingdom. It has already received half a million signatures that were presented to Prime Minister Yingluck Shinawatra on Wednesday.

Since coming into force in 1975, CITES has placed some 35,000 species of animal and plants under its protection, tightly controlling and monitoring their international trade.

The 177 countries who have signed up to the convention -- and must undertake measures to implement its decisions at home -- will be seeking to add certain names to the protected list during the meeting, which ends on March 14.

With poaching continuing to devastate some species, there will also be pressure to find tougher tactics to curb the networks supplying voracious demand from Asia, where wild animal parts are sought as trophies and for their supposed medicinal properties.

Rhinos, which have been on CITES's Appendix I -- denoting species threatened with extinction -- since 1977, have suffered from an explosion in poaching in recent years.

Some 668 rhinos were slaughtered in South Africa in 2012 -- up from just 13 in 2007.

The trafficking of rhino horn to Asia, where it is prized in traditional medicine, "continues to be one of the most structured criminal activities currently faced by CITES", according to its secretariat's report.

In a bid to end the bloodbath, Kenya has proposed a moratorium on the export of trophy horns of white rhinos from South Africa and Swaziland, which are currently exempt under the international embargo.

But the solution is not favoured by some environmentalists.

Trophy hunting brings in much-needed cash and "has actually helped the rhino population recover" as it encourages game reserve owners to maintain rhino numbers, said Richard Thomas, a spokesman for TRAFFIC.

The wildlife monitoring network is calling instead for "a lot of pressure and encouragement" on rhino horn destination countries, particularly Vietnam, seen as the main driver of global demand.

A similar strategy is being used for elephants. In the face of increased poaching, CITES is urging countries to take stronger measures to enforce the ban.

WWF and TRAFFIC have called for sanctions against Nigeria, the Democratic Republic of Congo and Thailand, which it says have flouted the law for years.

A range of sharks -- Porbeagle, Oceanic Whitetips and three species of hammerhead sharks -- will also be up for discussion at the Bangkok conference, amid growing calls for their inclusion for greater regulation of the shark fin trade.

Similar proposals to protect the sharks -- whose fins are prized in Asia -- failed in the face of opposition from a group of Asian countries concerned about their fishing industries.

But "it is highly likely that the shark proposals will be adopted this time", said Susan Lieberman, director of international policy at the Pew Environment Group, adding that all the shark species were "highly vulnerable".

CITES, which on Sunday celebrates 40 years since its inception in 1973, is also looking to strengthen protection for multiple plant species, including Madagascan ebony and rosewood from a host of countries.