the plastic banding used to secure boxes packs of timber etc is remarkably strong and most people resort to a cutting implement of some sort to remove it when most of the time you don't need to.
Step 1: Locate the Joint
simply work round the strapping until you find the double thickness bit where the ends overlap and are fused together
Step 2: Twist Band 180°
the outer surface is normally welded smooth and impossible to get even a knife blade in the joint. grasp the strapping and twist it though 180° so the inside is now on the outside
Step 3: Grasp and Pull
on what was the inside there is normally a open overlap of about 1/2-3/4" (12-15mm) grip it between thumb and fore finger bend up 90° and pull, the fused joint simply peels apart. no cutting required.