New perovskite-related oxides of Ru-V have been prepared and evaluated as catalysts for the partial oxidation of natural gas to synthesis gas. Their activity has been compared with that of Ru metal supported on alumina. Ba3NiRuTaO9 adopts the 6H hexagonal perovskite structure (a = 5.754(3) Angstrom, c = 14.119(9) Angstrom). At 900 degrees C it can facilitate 95% conversion of CH4 with a 98% selectivity for synthesis gas formation and at 800 degrees C it catalyses the total conversion of C2H6 with a 94% selectivity for synthesis gas formation. When a mixed CH4/C2H6/O-2 stream flows over this oxide at 900 degrees C, selective oxidation of ethane to synthesis gas is observed. The bulk structure of the perovskite catalyst remains unchanged, and no carbon deposition is observed during the course of these reactions. Although supported Ru metal gives a catalytic performance similar to that of Ba3NiRuTaO9, it also catalyses carbon formation when higher hydrocarbons, e.g. ethane, are present.