  We investigate the effects of the radiatively-generated tan beta-enhanced
Higgs-singlet Yukawa couplings on the decay $\Upsilon\to \gamma A_1$ in the
NMSSM, where $A_1$ is the lightest CP-odd scalar. This radiative coupling is
found to dominate in the case of a highly singlet Higgs pseudoscalar. The
branching ratio for the production of such a particle is shown to be within a
few orders of magnitude of current experimental constraints across a
significant region of parameter space. This represents a potentially observable
signal for experiments at present B-factories.
