Atomic structure data and effective collision strengths for 1s2 2s2 2p6 3s2 3p6 3d10 and 54 fine-structure levels are contained in the configurations 1s2 2s2 2p6 3s2 3p6 3d9 4l (l =s,p,d,f) for the nickel-like Ta ion.These data are used in the determination of the reduced population for the 55 fine structure levels over a wide range of electron densities (from 1021 to 1023) and at various electron plasma temperatures.The gain coefficients for those transitions with a positive population inversion factor are determined and plotted against the electron density.