The UN body with the power to ban trade in endangered animals and plants starts a triennial meeting in Doha on Saturday with bluefin tuna, African elephants and polar bears on the docket.
Among the 41 proposals on the table, one put forward by Tanzania and Zambia would seek to reopen trade in ivory, currently under a nine-year moratorium that started in 2008.
Most other African nations oppose the move, backing a competing measure that would extend the ban another decade.
At the CITES meeting in Qatar from March 13-25, Tanzania is asking the 175 members to allow it to sell almost 200,000 pounds of ivory. It noted in its proposal that its elephant population has risen from about 55,000 in 1989 to almost 137,000, according to a 2007 study.
Zambia wants to sell 48,000 pounds of ivory. Zambia says its elephant population of 27,000 is steadily increasing.