Mechanical processing of natural fibres can be used to produce large quantities of clean and refined fibres. However, this often results in fibre damage when used alone, thereby affecting the quality of fibres produced, and it generally makes them of insufficient quality for high-performance composite applications. In contrast, the use of biological agents such as enzymes have become a rapidly expanding area of research for producing high quality fibres, but this is still limited to pilot scales. This paper reports the effect of synergizing the salient features of mechanical processing (using a super masscolloider) and enzymatic treatment, on the structure and properties of harakeke (indigenous New Zealand flax) fibre. The cellulose fibres produced are characterized for their potential use as reinforcement in composites. Results show that the combination of mechanical processing with enzymatic treatment could help to overcome the limitations of both processes.