Te Rauparaha then mounted a major expedition against Kaiapoi Ngāi Tahu in the summer of 1831–32. Ngāi Tahu, lacking muskets to repel the armed Ngāti Toa, took a defensive strategy and hoped that Ngāti Toa would not be able to penetrate the wooden palisades surrounding the pā. The ensuing siege lasted for three months. However, during a skirmish between the two tribes, a shelter caught fire. Fanned by the nor'wester, the palisades quickly ignited, allowing Ngāti Toa warriors to enter the village, capture its leaders and kill the people. Ngāti Toa then attacked the Banks Peninsula tribes, taking the principal fort at Ōnawe, in Akaroa Harbour.