Woman, 41, arrested after eight-year-old boy found dead

A woman has been arrested after the death of an eight-year-old boy on Victoria's Mornington Peninsula.

The youngster's body was found on Thursday afternoon and a 41-year-old woman, known to the boy, was arrested at the Tootgarook address, police said.

"Police are yet to establish the exact circumstances surrounding the death however it is being treated as suspicious at this stage," a police statement said.

Investigators are not looking for anyone else in relation to the incident.

Anyone with information is encouraged to call Crime Stoppers 1800 333 000 or use the online reporting page.