Abstract: A neck block of a moulding tool for the production of a hollow body preform by means of injection moulding, wherein the neck block has a main body with a shaping surface which is adapted to the external contour of a neck portion of the hollow body preform to be produced and is provided to come into contact in the injection moulding operation with the neck portion of the hollow body preform, wherein furthermore there is provided at least one cooling passage for a cooling fluid which at least portion-wise extends substantially parallel to the shaping surface. The neck block is further provided with an inlet and an outlet and an inlet passage and an outlet passage which connect the inlet and the outlet respectively to the cooling passage. The cooling passage is arranged closer to the shaping surface than the inlet and the outlet.