The present invention relates to a method and apparatus for positioning a disc, such as a barrier disc (20), in a closure (40). In particular, the invention relates to a method and apparatus for positioning a barrier disc (20) in a self-sealing moulded plastic closure (40) having a sealing fin arrangement (22) for providing a seal when the closure (40) is appropriately applied to a finish of a container (30). The method comprises the steps of providing a barrier disc (20) in a position ready for insertion within the closure (40); pressing the barrier disc (20) relatively into the closure (40) such that at least a portion of the disc (20) is positioned at least adjacent the top panel thereof; and applying a fluid pressure to the barrier disc (20) such that the entire disc is forced into a position at least adjacent the top panel. The apparatus comprises an insertion station for supporting the closure (40) through the disc positioning process and a tool (50) that is movable relative to the insertion station to drive the disc (20) relatively into the closure (40). The tool (50) comprises a plunger (55) adapted to press the disc (20) into the closure (40) such that at least a portion of the disc (20) is adjacent the top panel thereof, and a fluid flow passage through which fluid travels to apply fluid pressure to the disc (20) and force the entire disc (20) past the sealing fin (22) and into a position at least adjacent the top panel.