Cigarette packets are assembled by a method that involves dabbing or spraying a cold-setting adhesive onto selected areas of a blank fed along the wrapping line of a packaging machine, whereupon the blank is folded to form a packet; should there be a break in operation of the machine following the application of the adhesive, persisting for a certain length of time, the method includes a heat-reactivation step whereby the adhesive applied previously to the blank is warmed to a given temperature so as to restore its bonding properties and guarantee the ultimate stability of the assembled packet.