The Vatican has published new instructions on cremation, ordering Catholics to keep ashes in a sacred place rather than at home.

The remains of the faithful should be left in consecrated ground such as a cemetery plot, the ruling says.

Church authorities also state that ashes must not be scattered in the air, on land or at sea, nor preserved in mementos, pieces of jewellery or other objects.

The document acknowledges that the practice of cremation has "notably increased in many countries" since its banning by the Vatican was lifted in 1963.

It goes on to warn, however, that "new ideas contrary to the church’s faith have become widespread".

The guidance also stresses that the church would prefer that bodies be buried, in line with Christian faith in resurrection.

"In circumstances when cremation is chosen because of sanitary, economic or social considerations," it says, "this choice must never violate the explicitly stated or the reasonably inferable wishes of the deceased faithful."

The document adds, however, that the church has no doctrinal objections to the practice, "since cremation of the deceased’s body does not affect his or her soul".

But Catholics are instructed to store ashes in a sacred place "which has been set aside for this purpose, and so dedicated by the competent ecclesial authority".

This, the guidance says, "ensures that they are not excluded from [prayers]" and "prevents any unfitting or superstitious practices".

Only in "grave and exceptional cases dependent on cultural conditions" are Catholics permitted to keep ashes in a domestic residence.

Even in these circumstances, cremated remains must be stored in one home rather than divided among various family members, it states.

The Vatican guidelines, 'Ad Resurgendum cum Christo', were released ahead of Halloween, traditionally a day of remembrance for the dead.