A needle (10) for a surgical instrument for removal of diseased or unwanted tissue comprises a hollow elongate needle shaft (12) having a needle tip (14) for cutting tissue at a distal end of the needle shaft (12). The needle tip (14) is flared in at least one plane and has a flattened posterior lip (16) and a curved anterior lip (18) to produce a substantially D-shaped tip mouth (20) in a plane that is substantially orthogonal to a central longitudinal axis C-O-C' (the needle axis) of the needle (10). A major axis A-A' of the tip mouth (20) is larger than an outer diameter of the needle shaft 12 and a minor axis B-B' is smaller than the major axis A-A'. The asymmetry of the tip mouth provides improved cutting action during phacoemulsification.
