Deuteron particle induced reactions for generation of 64Cu used in diagnostic and therapeutic nuclear medicine and its possible short lived contaminant 61Cu were investigated with the stacked foil activation technique on natural nickel targets up to E d = 20.5 MeV. Excitation functions for the reactions 64Ni(d,2n) 64Cu and natNi(d, x) 61Cu are obtained by gamma spectroscopy and are compared with earlier literature values. Thick target yields have been deduced from the experimental cross sections and the predictive capability of the ALICE-IPPE, EMPIRE II and GNASH model codes is tested.