The present investigation focuses on the kinetics of hydrogen absorption in Mg2Ni powders subjected to thermal or mechanochemical activation. The process was initially carried out under isobaric-isothermal conditions in a mechanochemical reactor at rest. Once the static hydrogen absorption process approached completion, the system was subjected to mechanical activation at constant hydrogen pressure. The mechanical treatment of powders induced further hydrogen absorption at rates depending on the processing intensity. The observed mechanochemical effect is related to the generation of reactive surfaces when mechanical loads apply on powders. The reactive surface area involved in the mechanochemical hydrogen absorption and the duration of the absorption process are roughly estimated.