A growing, wealthier middle class in East Asia and a communication boom are some of the causes for the increase in rhino poaching, conservation agencies said on Wednesday.

"There is a growing middle class in East Asian society that can afford to buy rhino horn... which they use as medicine," World Wildlife Fund (WWF) spokesman Joseph Okori told reporters in Johannesburg.

Rhino horn is incorrectly believed to treat cancer, among other diseases, in some Asian countries.

Spokesman for rhino-conservation agency TRAFFIC, Tom Milliken, said technological advances in communication had affected the increase in rhino poaching.

"There are 100 million cellphones in Africa. Everyone is connected now. A guy can make a call from a game reserve and say 'I've got the horn, come pick me up'. Then a car is [organised] to pick him up and in a day or two he can be on a flight out of the country. This was not happening years ago".

He also attributed the rise in rhino poaching to the growing Asian presence in Africa.

"This is organised crime... by Asian-run, African-based criminal syndicates."

He provided pictures of a Vietnamese website selling bowls made from rhino horn, as well as websites with prices and pictures of raw rhino horn.

A photograph was displayed of a bowl with a rough inside "which one uses to grind down the rhino horn, and then it is presumed water is added to the ground horn [and consumed]".

Milliken clarified that rhino horn was not used as an aphrodisiac.

"These people do not use rhino horn as an aphrodisiac, and it is very frustrating to see these incorrect claims made by the media."

The WWF urged the public to dust off their vuvuzelas and participate in "Make a noise for rhino" day on September 22.

It was part of a campaign to support the country's "rhino warriors", the men and women who risked their lives daily against the gangs running the illegal rhino horn trade, said Okori.

This year, 188 rhino had already been poached in South Africa.

Apart from blowing vuvuzelas and tooting car hooters on September 22, the WWF encouraged people to make donations at www.wwf.org.za. which would be used to buy anti-poaching equipment for guards, including binoculars, radios, night-vision gear, body armour and tracking devices.