  Consistently constrained WZWN models on G/{S x U(1)^n} is given by
constraining currents of the WZWN models with G. Poisson brackets are set up on
the light-like plane. Using them we show the Virasoro algebra for the
energy-momentum tensor of constrained WZWN models. We find a G-primary which
satisfies a classical exchange algebra in an arbitrary representation of G. The
G-primary and the constrained currents are also shown to obey the conformal
transformation with respect to the energy-momentum tensor. It is checked that
conformal weight of the constrained currents is 0. This is necessary for the
consistency for our formulation of constrained WZWN models.
