The mailing campaign was created by specialist fundraising agency DMS, part of the Direct Marketing Group.
It encourages IFAW supporters to respond by sending an action card to the minister for biodiversity, Joan Ruddock, calling on the UK government to prevent China from being able to trade legally in ivory.
An agreement has been made by the Convention on International Trade in Endangered Species for the stockpile of legal ivory to be sold in the near future. The convention is meeting in July to vote on whether China will be approved as a trading partner for the stockpile.
IFAW, which is a standing committee member of CITES, wants to prevent China, the world's largest trader in illegal ivory, from importing any legal ivory stockpiles, which it fears will allow traders to launder illegally poached ivory.
Nikki Kelly, wildlife trade campaigner for IFAW, said: "IFAW has worked relentlessly to protect elephants from the devastating effects of poaching. Key to this ongoing effort is to prevent China from flooding the market with ivory.
"If given permission to import large quantities of ivory, it will mean more of these magnificent creatures will be under further threat from poachers."
Mark Collins, IFAW account director at DMS, said: "We have created a communication which highlights the suffering of elephants and gives IFAW supporters the opportunity to make a real difference in the fight against poaching."