This paper describes the proposal of a benchmark activity. The objective of the proposed eddy current benchmark problem is to evaluate accuracy of various numerical or semi-analytical methods in predicting an eddy current probe multi-frequency response. The probe has a complicated structure and it consists of a cylindrical ferrite core with five symmetrically placed columns. The probe was used to test plates made from nickel-base superalloy INCONEL 600. In the plate a set of defects were introduced. An AC currents consist of 15 harmonic components are applied to the excitation coils. In all cases the specimens were examined by placing the probe on the reverse side of the flaws. The acquired data will be send by email to all participants of the benchmark's activity.