Oxidation kinetics based on Kissinger–Akahira–Sunose analysis of high Cr ferritic steel synthesised by mechanical alloying of elemental powder blend of 84Fe–13·5Cr–2·0Al with 0·5 nano-Y2O3 (all in wt-%) dispersion followed by cold compaction with 250 MPa pressure and sintering in vacuum (10−6 mbar) at 1000°C for 1 h have been investigated under isothermal (600–900°C for up to 50 h) and non-isothermal conditions (50–1200°C with heating rates of 10, 20, 30 or 40°C min−1). Mechanism of oxidation was taken place by counterionic transport of oxygen from surface to interior and cations (Cr3+/Fe3+) from the interior to the surface through grain boundary at low oxidation temperature (∼600°C) and through grains at high oxidation temperature (700–900°C). Early formation of Cr rich spinel layers on the surface improves the oxidation resistance by acting as the diffusion barrier against counterionic transport of ions during oxidation.