This paper describes preliminary findings in the development of a software tool that will facilitate the design, planning and assessment of wave farms. A third generation spectral wave model (TOMAWAC) has been modified in order to allow the assessment of wave energy converter (WEC) power absorption in isolation and in arrays of arbitrary layout. Following the development of the core functionality, the performance assessment of large WEC arrays can benefit from this type of model due to its computational efficiency compared to other methods. The modelling methodology and a series of generic considerations regarding pre- processing aspects are overviewed here. Initial results are compared with those obtained via an independent numerical model (a boundary element method) that takes into account additional effects such as phase-resolved radiation and diffraction processes. The assessment includes a commentary on the influence of array spacing on results accuracy. The key findings include considerations regarding the potential linkage of spectral-domain solvers to a generic WEC farm modelling tool under development.