March 24, 2017 0159 GMT
Addis Ababa city spokeswoman Dagmawit Moges said most of the dead are women and children, and more bodies are expected to be found in the coming hours, AP reported.
The landslide late Saturday leveled more than 30 makeshift homes of squatters living inside the Koshe landfill, said Moges, AFP reported.
About 150 people were there when the landslide occurred, resident Assefa Teklemahimanot told The Associated Press. Addis Ababa Mayor Diriba Kuma said 37 people had been rescued and were receiving medical treatment.
The Koshe site has for more than 40 years been one of the main garbage dumps for Addis Ababa, a rapidly growing city of some four million people.
Many people at the landfill had been scavenging items to make a living, but others live there because renting homes, largely built of mud and sticks, is relatively inexpensive.
According to AP, around 500 waste-pickers are believed to work at the landfill every day, sorting through the debris from the capital's estimated four million residents. City officials say close to 300,000 tons of waste are collected each year from the capital, most of it dumped at the landfill.
The resumption of garbage dumping at the site in recent months likely caused the landslide, Assefa said. The dumping had stopped in recent years, but it resumed after farmers in a nearby restive region where a new garbage landfill complex was being built blocked dumping in their area.
Since 2010, city officials have warned that the landfill was running out of room and was being closed in by nearby housing and schools.
City officials in recent years have been trying to turn the garbage into a source of clean energy with a $120 million investment. The Koshe waste-to-energy facility, which has been under construction since 2013, is expected to generate 50 megawatts of electricity upon completion.
Ethiopia, which has one of Africa's fastest growing economies, is under a state of emergency imposed in October after several months of sometimes deadly protests demanding wider political freedoms.