An apparatus and method producing a plait-like portion on a tubular packaging casing, which accommodates a filling material includes a plait-like portion at least approximately free of filling material, extending along a longitudinal plait-axis. The apparatus comprises a first displacer unit with a first pair of displacer elements reversibly movable between an opened and a closed position perpendicular to the longitudinal plait-axis. A displacer clearance is created between the first pair of displacer elements, which surrounds the longitudinal plait-axis, in which the tubular packaging casing is being gathered, when the first pair of displacer elements is in the closed position. The apparatus comprises a second displacer unit with a second pair of displacer elements also being reversibly movable between an opened and a closed position perpendicular to the longitudinal plait-axis. A displacer clearance is created between the second pair of displacer elements, similar to first pair of displacer elements.