Non-linear behaviour of the m = 1 reconnecting mode is demonstrated in a current-carrying helical system with ι(r) = ισ(r) + ιB(r) > 3. Here, ισ(r) and ιB(r) denote rotational transforms due to plasmacurrent and external helical fields, respectively. For dιB(r)/dr < 0, the m = 1 reconnecting mode becomes linearly unstable. The non-linear regime of the m = 1 reconnecting mode is divided into two stages. The first stage maintains a linear eigenmode, whereas the second stage shows rapid non-linear growth and its mode structure is similar to the m = 1 tearing mode. The saturation level of the kinetic energy and magnetic island formation of the m = 1 reconnecting mode are comparable to those of the m = 1 tearing mode; the reconnecting mode shows, however, slower non-linear evolution.