JOHANNESBURG • Global conservationists and policymakers are meeting in South Africa from today to chart a way forward in the fight against escalating wildlife trafficking that could drive some species into extinction.

The plight of Africa's rhinos and elephants, targeted for their horns and tusks, is expected to dominate 12 days of talks in Johannesburg on the Convention on International Trade in Endangered Species of Wild Fauna and Flora (Cites), held every three years.

Illegal wildlife trade is valued at around US$20 billion (S$27.2 billion) a year, according to Cites, and is ranked as the fourth-largest illicit business in the world, after arms, counterfeit goods and human trafficking.

The gathering is described by organisers as the largest and most important Cites event since its founding in 1975. Participants are expected to assess whether to toughen or loosen trade restrictions on some 500 species of animals and plants. On till Oct 5, the event is being attended by around 3,500 delegates from 182 member nations.

The Cites treaty, with 182 countries and the European Union as signatories, protects wild animals and plants against over-exploitation through commercial trade, and came into force in 1975.

"Much of the international attention will focus on the ivory of the African elephant and the horn of the Southern White Rhinoceros, and on combating their illegal trade," said Cites secretary-general John Scanlon ahead of the event.

Cites banned trade in rhino horn 40 years ago, but prohibition has not reduced illicit hunting, which has boomed recently in South Africa. Around 5,000 white rhinos - a quarter of the population - have been slaughtered over the past eight years; most were killed in South Africa, which is home to 80 per cent of the world's rhinos.

Rhino poaching is driven by insatiable demand in Vietnam and China for the horn, which is mistakenly believed to have medicinal powers.

Vietnam is expected to come under hard scrutiny at the conference.

"Vietnam's poor law enforcement record speaks for itself: Ending the illegal rhino horn trade and helping to save Africa's rhinos is clearly not a priority for the government," said World Wide Fund for Nature delegation head Ginette Hemley.

"Cites must take a tough line", by forcing Vietnam to swiftly prosecute traffickers and traders or face trade sanctions for all other regulated species, she noted.

On Wednesday, British Environment Secretary Andrea Leadsom announced what will be one of the world's toughest bans on sale of modern-day ivory.

"This ban will send the message that the ivory trade is a thing of the past. I hope it increases pressure on other nations to implement bans and save our elephants before they disappear," she said.

In a statement issued in London, Britain's Department for Environment, Food and Rural Affairs said the new action to tackle the illicit trade would be discussed at the conference.

Cites banned international commercial trade in African elephant ivory in 1989, but illegal poaching of endangered elephants for their tusks persists at dangerous levels.

Results from the world's largest wildlife census, released last month, showed that savannah elephant populations declined by 30 per cent in the seven years up to 2014.

As a reflection of how pressing the issue is, New York officials said on Thursday that the city had seized US$4.5 million worth of illegal elephant ivory items in what they described as the biggest bust in the state's history.

The ivory came from at least 12 slain animals, the officials said.

"We are going to dry up... a market that only fuels the slaughter of elephants," said Manhattan District Attorney Cyrus Vance. "It is inexcusable, it is immoral."

Undercover police posing as buyers seized the items at a midtown Manhattan art and antiquities store. The store owners were indicted on charges of illegal commercialisation of wildlife. They face hefty fines and up to three years in prison.

AGENCE FRANCE-PRESSE, XINHUA