  The behaviour of a d-dimensional vectorial N=3 model at a m-axial Lifshitz
critical point is investigated by means of a nonperturbative renormalization
group approach that is free of the huge technical difficulties that plague the
perturbative approaches and limit their computations to the lowest orders. In
particular being systematically improvable, our approach allows us to control
the convergence of successive approximations and thus to get reliable physical
quantities in d=3.
