A statement by Environment Minister Pierre Hélé said the government had information that a ship called the NV Nashville was dumping waste off the coast of west Africa, but provided no details of its location or movement.
The minister called on his counterparts in neighbouring countries to be on the lookout for any suspicious vessels.
"Our friends in the west are very dangerous people," ministry official Benoît Bitjocka told AFP news agency.
"They treat Africa like a dustbin."
This is not the first time European ships have dumped waste of the coast of west Africa.
In 2006, toxic material was dumped from the Probo Koala cargo ship in waters off Côte d'Ivoire. According to an Ivorian court, the waste was responsible for killing 17 people, and poisoning thousands.
The company that leased the ship, London-based multinational Trafigura, paid Abidjan 152 million euros in compensation to avoid legal proceedings.