Reversing mechanism for an agricultural baler wherein the reversing mechanism includes a driving pulley mounted for rotation together with the conveying elements provided to be connected to the axis such that the axis and the conveying elements can be rotated along the working direction by a driving belt engaging the driving pulley. A tensioning pulley is provided for controlling the tension of the driving belt such that by engaging the driving belt, the driving belt engages the driving pulley such that the axis is rotationally driven by the driving belt, and by sufficiently releasing the driving belt, the driving belt no longer engages the driving pulley and the axis is no longer rotationally driven by the driving belt.