Positioning and/or transfer assembly comprising: • an endless conveyor belt consisting of a conveying part for carrying an object and a return part; • a first and a second roller (12, 13) arranged inside the endless conveyor belt, each roller (12, 13) having a first and second end (22, 24, 26, 28); • a frame; • a mounting system comprising a first mounting part mounting the first end of the first roller rotatably to the frame, a second mounting part mounting the second end of the first roller rotatably to the frame, a third mounting part mounting the first end of the second roller rotatably to the frame, and a fourth mounting part mounting the second end of the second roller rotatably to the frame; and, • an actuator system for moving the conveyor belt in a lateral direction with respect to the frame, wherein the actuator system comprises a first lateral actuator arranged to move at least a part of the first roller in a direction parallel to the rotational axis of the first roller; wherein the first roller is longitudinally divided into at least two, such as three or four, longitudinal segments (51, 52, 53, 54) and said first lateral actuator is arranged to move at least one of the longitudinal segments (51, 52, 53, 54) of the first roller parallel to the rotational axis of the first roller with respect to another of said longitudinal segments (51, 52, 53, 54) of the first roller; and wherein a length direction of the conveyor belt is defined by the conveying direction of the conveyor belt and extends transverse to the rotational axis (106, 107) of the first and second roller, characterized in that at least one of the first and second mounting part (21, 23) comprises a first tensioning system arranged for tensioning the conveyor belt in said length direction for simultaneously counteracting a change of tension in the belt due to laterally moving the at least one of the longitudinal segments of the first roller; and wherein the first and second end (22, 24) of the first roller are moveable relative to each other in said length direction by the first tensioning system in response to a difference in length and/or in belt tension between the longitudinal edges (100, 101) of the conveyor belt; and wherein the actuator system further comprises a second lateral actuator arranged to move at least a part of the second roller in a direction parallel to the rotational axis of the second roller and the second roller is longitudinally divided into at least two, such as three or four, longitudinal segments and said second lateral actuator is arranged to move at least one of the longitudinal segments of the second roller parallel to the rotational axis of the second roller with respect to another of said longitudinal segments of the second roller; and wherein a first end and second end of the second roller are moveable relative to each other in the length direction of the conveyor; and wherein at least one of the longitudinal segments of the first and the second roller (12,13) is provided with a metal plate at one lateral side of the longitudinal segment and with another metal plate at the other lateral side of the longitudinal segment; and the first and the second lateral actuator comprises at least two controllable magnets (62, 63), each positioned at one lateral side of the longitudinal segments, wherein the controllable magnets are positioned in front of at least a part of a trajectory of the metal plates (61, 64), wherein a strength of the magnetic force of the magnets (62, 63) on the metal plates (61, 64) on both lateral sides are controllable such that the longitudinal segment is moved by the magnets (62, 63) in the lateral direction and back. • an endless conveyor belt consisting of a conveying part for carrying an object and a return part; • a first and a second roller (12, 13) arranged inside the endless conveyor belt, each roller (12, 13) having a first and second end (22, 24, 26, 28); • a frame; • a mounting system comprising a first mounting part mounting the first end of the first roller rotatably to the frame, a second mounting part mounting the second end of the first roller rotatably to the frame, a third mounting part mounting the first end of the second roller rotatably to the frame, and a fourth mounting part mounting the second end of the second roller rotatably to the frame; and, • an actuator system for moving the conveyor belt in a lateral direction with respect to the frame, wherein the actuator system comprises a first lateral actuator arranged to move at least a part of the first roller in a direction parallel to the rotational axis of the first roller;