A method for the production of pre-compressed elements made of composite material, such as blocks, panels, prefabricated walls, beams, and slabs for structural or non-structural use in the building sector, comprising the following steps: providing an amount of a dry fibrous organic material (7); providing a first outer casing made of a heat-meltable bioplastic material (2) for containing the fibrous material for the formation of a composite material; providing a plurality of inner casings containing portions of said fibrous material; compressing the composite material comprising the fibrous material (7) and the outer and inner casings of plastic material; heating the composite material; and cooling the composite material.