An injection moulding assembly (10) comprising a male moulding member (11) surrounded by a female moulding member (12) forming a void (13) between them that upon injection of molten plastics into the mould a container can be formed. The moulding assembly includes a guide rod (14) and ejection flange (16) and a pair of ejection flange guide rods (17 and 18), an air vent valve (15) and an injection passage (19). The male member (11) includes in this embodiment eight grooves (20) unevenly spaced so that the partially hardened container formed in the injection mould can be pushed from the mould using the ejection flange (16) while the container is sufficiently green to enable the ribs formed in the grooves (20) to move over the surface of the male mould (11) during the ejection process.