An Andreev-reflection study of MgB₂/ Ag planar junctions as a function of temperature and magnetic field is reported. The differential resistance (dV/dI) versus voltage (V) characteristics exhibited a distinct double minimum feature. This, together with a comparison of Blonder-Tinkham-Klapwijk theory of isotropic super-conductor, indicates that data are not consistent with the weak-coupling BCS theory. This is further supported by unusual temperature and magnetic-field dependence of the tunneling characteristics. The results are dis-cussed using various existing theories.