To overcome the previous unsuccessful attempts for the study by Electron Paramagnetic Resonance (EPR) spectroscopy of the defects at the 6H-SiC/SiO2 interface we have studied thermally oxidised porous SiC layers. Two paramagnetic defects were detected after furnace oxidation at 1000degreesC. The first defect is characterised. by an EPR spectrum with axial symmetry and g-factors of g(//)=2.0023 and g(perpendicular to)=2.0031 and a superhyperfine structure of 11.3G with three Si neighbour atoms. From the analogy between this defect and the Pb centres at the Si/SiO2 interface we attribute this defect to a .-C-Si-3 carbon dangling bond centre in the SiC interface plane. The second centre has an isotropic g value of 2.0028 and is tentatively attributed to a C related defect in the non stoichiometric oxide in the near interface region.