This paper will discuss some of the key field investigation and processing methodologies that can underpin the definition of shear wave velocity-based seismic site classification metrics. The recent update to the National Seismic Hazard Model has triggered an evolution of the approach to site classification in New Zealand and shifted the focus towards the time averaged shear wave velocity over the top 30 m of the profile (Vs30) as a key site classification metric. However, to provide robust estimates for Vs30, the industry needs to have a good understanding of the advantages and limitations of the different site investigation methods that are available. The methodological constraints related to the size of a site and the presence of existing infrastructure will be discussed. The influence of the variation in geologic conditions across the country on the choice of different methods will be highlighted. Along with single methods, this paper will highlight how different methods can be used in combination to improve confidence and reduce uncertainty. The general costs of different methods will be discussed and how projects of different scales and importance could approach site classification. Across each method the interpretation approach will be discussed, including the translation of these to site classification metrics.