Another severed human foot has been discovered washed ashore on Canada's Pacific coast, but police are no closer to solving the gruesome mystery on where they are coming from.

The shoe-clad foot was discovered on Thursday on a small uninhabited island south of Vancouver in the Strait of Georgia, and is the fourth discovered in the region in the past 10 months.

All four cases involved right feet, and each was found on a different island. The earlier feet were also still in shoes.