Prince William addressed an audience in Thailand via video as part of a conference to 'ensure the survival of the planet's wildlife'.
Some 177 government and agencies have been trying to halt the trade in ivory and rhino horn in an international agreement known as CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora).
The Duke of Cambridge said: "There will undoubtedly be differences of opinion from time to time, but I know that you are all bound by a common objective: to ensure the survival of the planet's wildlife.
"It is 40 years to the day since the convention was signed in Washington DC, so please join me in wishing CITES a very happy 40th birthday."
An international conference to halt the rise in ivory and rhino horn poaching ended in Bangkok, with campaigners feeling 'disappointed'.
Wildlife campaigners believe an opportunity to halt the rise in ivory and rhino horn poaching has been missed at the CITES conference.
There appears to be a perfect storm and animals which have been on the planet for millions of years may be wiped out.