Forensic authorities in Colombia has said that at least 248 people have died in the Mocoa mudslide after heavy rains caused rivers to overflow in Colombia's Putumayo province.

"At the moment we have 248 dead bodies registered," media news quoted Carlos Eduardo Valdes, director of the National Institute of Forensic Medicine and Forensic Science on Sunday.

Hundreds were reported dead and several hundreds missing after torrential rains on Friday night caused three rivers surrounding Mocoa to overflow -- sending a torrent of mud surging through the city, media reported.

Reports of the exact number of those killed in the rugged, remote area varied.

The Colombian military on Saturday had said at least 254 were dead and around 400 more injured. While the Red Cross reported 234 deaths and said that 158 people were missing. A police officer was among the victims, federal officials said.

President Juan Manuel Santos has declared a state of emergency.