We investigate the effects of a perpendicular electric field applied to multilayer black phosphorus nanoribbons with zigzag and armchair edges. Within the context of the tight-binding model, we explore the electronic properties of these systems giving emphasis to the appearance of Dirac-like spectra, a transition that occurs when the gate density associated with the applied displacement field is greater than the critical value nc. We show that the confinement properties and the screening effects in such systems play an important role on the determination of nc, suggesting a scheme to determine the thickness, width and edge orientation of multilayered phosphorene nanoribbons.