Italian police on the island of Sardinia have discovered an illegal marijuana farm hidden behind a tiled shower wall.

A hatch in the shower compartment leads to the 500 square metre (5,381 square feet) farm containing more than 500 plants.

The vast farm was maintained behind a shower. Credit: AP

Police also seized a gun and bullets.

A video filmed and shared by Italian police shows the vast farm hidden behind a small opening in a shower.

The farm was contained within a house and police said they arrested a 30-year old man.