The woman's son has been arrested on the suspicion of killing her. (Representational)

A 26-year-old man from Madrid has been arrested on suspicion of killing his mother then cutting up her remains and storing them in Tupperware containers, Spanish police said on Friday.

The incident came to light when a friend of the missing 66-year-old contacted the police to say she hadn't seen her for about a month, prompting a patrol to visit the family home on Thursday.

On entering the house in the central Salamanca neighbourhood, "they found the woman, dismembered," with her "remains stored in different Tupperware boxes around the house," a national police spokesman said.

The son was immediately arrested on suspicion of killing his mother.

Police said the suspect had previously been arrested 12 times, for various reasons but in most cases.

Local media suggested the suspect had been engaging in cannibalism but there was no confirmation from the police.