An outlet tap assembly (1) for dispensing liquid packaged in flexible packaging bags is provided. The tap assembly comprises a tubular outlet member (2, 32) having a bore (8) therein, a tap (5, 6) at one end for controlling the flow of liquid through the bore, and a spike (3) at the opposite end for penetrating a plastic packaging bag. At least one aperture (4) communicates with the bore towards the inner end to allow liquid to enter from a bag into the bore. An endless clamping surface (11, 31) encircles the outlet member between the aperture and tap and a clamping element (12, 30, 35) having an endless clamping edge or surface (13) is movable axially on the outlet member so as to cooperate with the clamping surface on the outlet member to operatively clamp material of a flexible packaging bag therebetween. The outlet tap assembly has resilient means (16, 21, 26, 29, 33, 36) for urging the clamping element axially into engagement with the clamping surface on the outlet member automatically.