Empirical liquefaction potential assessment is generally based on the results of CPT, SPT or shear wave velocity (VS) measurement. In more complex or high-risk projects CPT and VS measurement are often performed at the same location commonly in the form of seismic CPT. However, combined use of both in-situ indices in one single empirical method has been limited. After the compilation of a case history database, the authors have developed a combined probabilistic method where the results of CPT and VS measurement can be used in parallel. The goal of this paper was to evaluate the prediction capability of the developed equation on an independent dataset of the 2010-2011 Canterbury Earthquake Sequence and to compare it with commonly used empirical procedures. It was found that the error index defined to quantify the false predictions is the largest for the recommended method but regarding the number of false predictions, it outperforms the other methods used for comparison.