A method of laser processing of a metallic material, in particular for laser cutting, drilling or welding of said material, by means of a focused laser beam having a predetermined transverse power distribution on at least one working plane of the metallic material, comprising the steps of: - providing a laser beam emitting source; - leading the laser beam emitted by said emitting source along a beam transport optical path to a working head arranged in proximity to said metallic material; - collimating the laser beam along an optical axis of propagation incident on the metallic material; - focusing said collimated laser beam in an area of a working plane of said metallic material; and - conducting said focused laser beam along a working path on the metallic material comprising a succession of working areas (T1, R1, T2, R2, T3, H), the method comprising shaping the laser beam, wherein shaping the laser beam comprises: - reflecting said collimated beam by means of a deformable controlled surface reflecting element having a reflecting surface with a continuous curvature including a plurality of independently movable reflection areas (200a-200r), and - controlling the arrangement of said reflection areas (200a-200r) to establish a predetermined transverse power distribution of the beam on at least one working plane of the metallic material as a function of the area of the current working plane (Π) and/or the current direction of the working path on the metallic material characterised in that the method further comprises the steps of: - delivering a flow of assist gas towards said area of the working plane of the metallic material along an axis of the assist gas flow, - translating the axis of the assist gas flow relatively to a predetermined working path on the metallic material, - detecting the current position and/or the direction of the current translation of the axis of the assist gas flow, - controlling the arrangement of said reflection areas (200a-200r) to establish said predetermined transverse power distribution of the beam in an area of the working plane on the metallic material comprised in a predetermined neighborhood around the axis of the assist gas flow and within a delivering area (G1-G4) of said flow, - automatically adjusting the position of the optical axis of propagation of the laser beam as a function of the detected current position and/or of the detected current translation direction of the axis of the assist gas flow. - providing a laser beam emitting source; - leading the laser beam emitted by said emitting source along a beam transport optical path to a working head arranged in proximity to said metallic material; - collimating the laser beam along an optical axis of propagation incident on the metallic material; - focusing said collimated laser beam in an area of a working plane of said metallic material; and - conducting said focused laser beam along a working path on the metallic material comprising a succession of working areas (T1, R1, T2, R2, T3, H), - reflecting said collimated beam by means of a deformable controlled surface reflecting element having a reflecting surface with a continuous curvature including a plurality of independently movable reflection areas (200a-200r), and - controlling the arrangement of said reflection areas (200a-200r) to establish a predetermined transverse power distribution of the beam on at least one working plane of the metallic material as a function of the area of the current working plane (Π) and/or the current direction of the working path on the metallic material - delivering a flow of assist gas towards said area of the working plane of the metallic material along an axis of the assist gas flow, - translating the axis of the assist gas flow relatively to a predetermined working path on the metallic material, - detecting the current position and/or the direction of the current translation of the axis of the assist gas flow, - controlling the arrangement of said reflection areas (200a-200r) to establish said predetermined transverse power distribution of the beam in an area of the working plane on the metallic material comprised in a predetermined neighborhood around the axis of the assist gas flow and within a delivering area (G1-G4) of said flow, - automatically adjusting the position of the optical axis of propagation of the laser beam as a function of the detected current position and/or of the detected current translation direction of the axis of the assist gas flow.