  We report the longitudinal resistivity and Hall effect measurements on the
noncentrosymmetric superconducting Mg$_{12-\delta}$Ir$_{19}$B$_{16}$ samples
with different critical transition temperatures. A strong temperature
dependence of the Hall coefficient $R_H$ and nonlinear magnetic field
dependence of the Hall resistivity $\rho_{xy}$ in wide temperature region are
observed, suggesting a strong multi-band effect in this system. Moreover, a
large magnetoresistance up to 20% is found at the field of 9 T. We also observe
the violation of the Kohler's rule from our magnetoresistance data, further
confirming the presence of multi-band effect in our samples. A detailed
analysis shows that the data can't be simply described within the two-band
scenario at low temperatures, so we argue that there may be more than two bands
contributing to the conduction of the samples.
