A method of laser processing of a metallic material (WP; M), in particular for laser cutting, drilling or welding of said material, by means of a focused laser beam having a predetermined transverse power distribution at at least one working plane (Π) of the metallic material (WP; M; M), 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 of said metallic material (WP; M; M); - collimating the laser beam along an optical axis of propagation incident on the metallic material (WP; M; M); - focusing said collimated laser beam in an area of a working plane (Π) of said metallic material (WP; M; M); and - conducting said focused laser beam along a working path (T; F) on the metallic material (WP; M) comprising a succession of working areas, 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 at at least one working plane (Π) of the metallic material (WP; M) as a function of the area of the current working plane (Π) and/or the current direction of the working path (T; F) on the metallic material (WP; M), characterised in that the method further comprises the steps of: - delivering a flow of assist gas towards said area of the working plane (Π) of the metallic material (WP; M) along an axis of the assist gas flow, - relative translating the axis of the assist gas flow along a predetermined working path (T; F) on the metallic material, - detecting the current position and/or the direction of the current translation of the axis of the assist gas flow, - wherein shaping of the laser beam further comprises: automatically controlling the transverse power distribution of the laser beam as a function of the detected current position and/or the detected current translation direction of the axis of the assist gas flow by 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 (Π) on the metallic material (WP; M) comprised in a predetermined neighborhood around the axis of the assist gas flow and within a delivering area of said 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 of said metallic material (WP; M; M); - collimating the laser beam along an optical axis of propagation incident on the metallic material (WP; M; M); - focusing said collimated laser beam in an area of a working plane (Π) of said metallic material (WP; M; M); and - conducting said focused laser beam along a working path (T; F) on the metallic material (WP; M) comprising a succession of working areas, - 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 at at least one working plane (Π) of the metallic material (WP; M) as a function of the area of the current working plane (Π) and/or the current direction of the working path (T; F) on the metallic material (WP; M), - delivering a flow of assist gas towards said area of the working plane (Π) of the metallic material (WP; M) along an axis of the assist gas flow, - relative translating the axis of the assist gas flow along a predetermined working path (T; F) on the metallic material, - detecting the current position and/or the direction of the current translation of the axis of the assist gas flow, - wherein shaping of the laser beam further comprises: automatically controlling the transverse power distribution of the laser beam as a function of the detected current position and/or the detected current translation direction of the axis of the assist gas flow by 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 (Π) on the metallic material (WP; M) comprised in a predetermined neighborhood around the axis of the assist gas flow and within a delivering area of said flow.