Using the formalism developed in the paper by Maxwell [Nucl. Phys. A 600 (1996) 509] a relativistic Love-Franey representation of the NN t-matrix has been obtained over the laboratory energy range from 500 to 800 MeV. The real and imaginary parts of this t-matrix are expanded separately in complete sets of on-shell Lorentz invariant amplitudes, which are represented by isoscalar and isovector "meson" exchanges. The masses associated with these exchanges are assumed to be independent of energy, while the coupling strengths and form factor masses are allowed to vary quadratically and linearly with energy, respectively. Direct and exchange contributions to the interaction are handled explicitly in the model. The model parameters are fit to the Summer 1997 Arndt amplitudes [Arndt and Roper, VPI and SU scattering analysis interactive dial-in program and data base (SAID)] and results given for various np and pp observables. The spin-averaged differential cross section and the vector asymmetry are generally reproduced quite well. The results for the other observables considered are not quite as good, especially at higher energy. @ 1998 Elsevier Science B.V.