Officers were called at 11.30am on Saturday after the body was found in the back garden of a home in Tunnel Avenue.
The woman, believed to be in her 50s, was pronounced dead at the scene.
She appeared to have suffered stab wounds.
Police believe they know who she is, and are informing her next of kin.
A man, also in his 50s, was arrested at the house on suspicion of murder.
Police say they believe the victim was known to the man who was arrested, but say it is not a “domestic incident”.
Cordons remain in place.
A post-mortem will take place at Greenwich Mortuary on 24 June.
Anyone with information that may assist police should call detectives from the Homicide and Major Crime Command on 020 8721 4054.