Active-powder biocidal composition comprising at least one copper salt and at least one zinc salt such that the molar ratio between the copper salt and the zinc salt is within the range of 10 to 1 and each copper and zinc salt, separately, has a solubility constant (Kps) within the range from a value greater than or equal to 1*10 -20 to a value less than or equal to 9*10 -6 . Also included is the biocidal composition that comprises the active-powder composition and a polymer, and the method for the production of said biocidal composition, which comprises: thoroughly mixing the salts in such a manner as to obtain a homogeneous distribution of an active-powder biocidal composition； controlling the mixing temperature such that it remains at approximately less than 50°C； and mixing the resulting mixture of active powders with a polymer.
