Prince William and his father Prince Charles delivered impassioned pleas on Tuesday for action against the illegal trade in wildlife which threatens some of the world's best loved animals.

Charles told a conference at St James' Palace in London that action must be taken against the poaching of elephants, rhinos and tigers for their ivory, horns and other parts to avoid the "irreversible tragedy" of their extinction.

The heir to the British throne said wildlife trafficking was "not only decimating critical endangered species, but is also a pervasive instrument in destabilising economic and political security".

He said local poachers had been replaced by increasingly sophisticated groups who would stop at nothing to win a part of a black market trade worth $10 billion a year.

"They are taking these animals, sometimes in unimaginably high numbers, using the weapons of war -- assault rifles, silencers, night vision equipment, and helicopters," he said.

He added: "As a father and a soon-to-be grandfather, I find it inconceivable that our children and grandchildren could live in a world bereft of these animals."

Charles' son William, whose wife Catherine is expecting his first child in July, also addressed the meeting of government officials, NGOs and private companies from around the world.

"I sincerely hope that my generation is not the first on this planet to consider elephants, rhinos or tigers as historical creatures -- in the same category as the Dodo."

Charles has long been a champion of conservation and is head of the British branch of global charity WWF -- a job once held by his father Prince Philip, the husband of Queen Elizabeth II.

William meanwhile is a patron of the Tusk Trust, a conservation charity, and has sought to use his charitable foundation to look at how to shape public opinion about the trade in animal parts.

"I think that the consumer deserves to know that the illegal animal parts' fashionable and luxurious image is at odds with the barbarity of how these animal parts are obtained," he said.

Elephants have long been hunted for their ivory tusks, while rhino horns are an expensive commodity in Asia, where consumers falsely believe the substance has medicinal properties.

British Environment Secretary Owen Paterson, who co-hosted Tuesday's conference with the royals, summed up the misguided value put on animal products by saying: "Rhino horn has the same medicinal value as one of my big toe nails."