Italian prosecutors believe pizza in the southern city of Naples may be baked in ovens lit with wood from coffins dug up in the local cemetery, Italian daily Il Giornale reports.

"Pizza, one of the few symbols of Naples that endures ... is hit by the concrete suspicion that it could be baked with wood from coffins," Il Giornale said on Monday.

Investigators in Naples are setting their sights on the thousands of small, lower-end pizza shops and bakeries that dot the city on suspicion that the owners may "use wood from caskets to keep ovens burning".

Naples's graveyard has long been a hunting ground for thieves: last year, 5000 flower pots were stolen from the cemetery.

"A gang might have set up a market for coffins sold to hard-hearted owners of bakeries and pizzerias looking to save money on wood," Il Giornale said.