Police from Pak Khlong San station, Siriraj Hospital medics and rescue volunteers responded to a call that human remains had been found near Tha Din Daeng pier.
The victim was aged between 20 and 40 years old. The corpse was found inside a plastic bag, which had been wrapped with another green plastic bag.
No clothing and no identification were found on the body. On her left wrist was a bracelet adorned with something that looked like a diamond. Medics also found evidence of a severe injury to the right side of her waist.
Sahaphop Kruekrat, 61, said he called the police after spotting a bag in the river with human legs sticking out.
Siriraj Hospital is performing an autopsy to identify the victim. Pak Khlong San police station said anyone who suspected the victim might be his or her relative could contact the police on (02) 438 1034.