A kinetic study of the mercury oxidation across a standard composition SCR catalyst under simplified flue gas conditions (12 % CO2, 5 % O-2, 5 % H2O, 5 ppb Hg, 10 ppm of HCl in air) is carried out in a lab-scale packed-bed reactor. A thorough analysis is presented of the experimental error on the Hg oxidation rates, reaction orders, and activation energy propagated from the uncertainty in the measured mercury concentrations, thereby revealing several important limitations of these lab-scale experiments. The effects are investigated of flue gas composition, temperature, and space velocity on the Hg oxidation efficiency of the catalyst, and the reaction order of O-2 and Hg are derived together with the apparent activation energy. It is confirmed that O-2 is zeroth-order while Hg is first-order in terms of the Hg oxidation rate. An activation energy of 34 +/- 7 kJ/mol is obtained. It is shown that the magnitude of the oxidation efficiencies increases with increasing amount of catalyst and temperature (from 150 to 350 degrees C).