The lateral load capacity of timber pile foundation systems are set out in NZS 3604. The most heavily loaded are anchor piles and braced piles which are required to have a capacity of 160 Bracing Units (BUs). Driven cantilever piles are required to have a capacity of 70BUs. At the maximum permitted height for these piles and considering the seismic response of timber pile foundation systems, the bending moment demand is 6.0, 4.7 and 4.4kNm respectively for anchor, driven cantilever and braced piles. 125mm square sawn timber piles meeting No.1 framing quality are sufficient for a bending demand of 4.8kNm. Hence the anchor piles need special care in their selection and proof testing is considered to be the only means to guarantee their strength. Ordinary piles carry vertical loads and therefore have a minimal required bending capacity.