Design optimisation of metal-clad cylindrical nanowire semiconductor lasers is undertaken. Attention is focused on structures having GaN as the material platform and utilising silver for the metal cladding. The lasing characteristics of such structures are explored using both the transfer matrix method and the finite element method for operating wavelengths from 330 to 830 nm and for metal cladding thicknesses in the range of 5??20 nm. Specifically, calculations are performed for the modal confinement factor, modal gain and device length across this wide parameter space. For representative structures, it is shown that lower-order TE and TM mode lasing can be supported in devices having cavity lengths of the order of 2 and 18 μm, respectively.