  In this paper we study the effects of hemispheric imbalance of magnetic
helicity density on breaking the equatorial reflection symmetry of the dynamo
generated large-scale magnetic field. Our study employs the axisymmetric dynamo
model which takes into account the nonlinear effect of magnetic helicity
conservation. We find that the evolution of the net magnetic helicity density,
in other words, the magnetic helicity imbalance, on the surface follows the
evolution of the parity of the large-scale magnetic field. Random fluctuations
of the $\alpha$-effect and the helicity fluxes can inverse the causal
relationship, i.e., the magnetic helicity imbalance or the imbalance of
magnetic helicity fluxes can drive the magnetic parity breaking. We also found
that evolution of the net magnetic helicity of the small-scale fields follows
the evolution of the net magnetic helicity of the large-scale fields with some
time lag. We interpret this as an effect of the difference of the magnetic
helicity fluxes out of the Sun from the large and small scales.
