The mass transport to a partially blocked surface on a rotating disc electrode when its angular velocity is submitted to small sinusoidal oscillations around a mean value has been analysed. From the quantitative treatment of the response of a single active site embedded in an otherwise conducting surface, it was inferred that the high frequency response of a partially blocked surface with active sites of the same size can be estimated. The response contains two time constants and its frequency analysis can provide the average size site and the active fraction of the interface. These predictions were compared with an experimental investigation using a photolithographic model of a partially blocked electrode. Good agreement between theory and experiment was obtained when the high frequency response was corrected for kinetic effects due to the finite rate of the chosen redox reaction and double-layer charging.