Embarking a force of more than 600 men at Kapiti, he took his fleet of war canoes to the mouth of the Waipara River, and then marched quickly down the coast to Kaiapoi, hoping to take the pā by surprise. However, although the pā was only thinly manned, most of the warriors having gone to Whakaraupō to escort Taiaroa on the first stage of his return to Otago, warning was given of some skirmishes by gunshots, and the gates were closed as the invaders arrived. Before Te Rauparaha could make a full-scale attack, the Kaiapoi force returned, accompanied by Taiaroa's men, and made their way into the pā from the rear by wading across the lagoon. Two frontal assaults having failed, Te Rauparaha began a siege of the pā which lasted three months. During this time Taiaroa made a bold sortie to the Waipara, hoping to destroy the invaders' canoes, but light axes could make little impression on the heavy hull timbers of large war canoes, and torrential rain made it impossible to burn them. As the siege seemed likely to be protracted it was then decided that Taiaroa should then return to Otago and bring up reinforcements. Finding that any direct assault was too open to the fire of the defenders, Te Rauparaha set his men to sap up to the walls. At first many were lost in this work, but by covering the trenches, and breaking their line with zig-zags, the head of the sap was at last brought to within a few feet of the pā. large quantities of manuka brushwood were then cut, tied in small bundles, taken to the head of the sap, and thrown into the trench against the palisades. For a time, the defenders were able at night to remove the greater part of this brushwood, but in the end the quantity was greater than they could deal with. Realizing that with the first southerly wind the invaders would fire the brushwood and thereby burn down the palisades, the Ngāi Tahu tried the desperate expedient of firing it themselves when the wind was nor’west, and driving away from the pā. But the wind changed suddenly, the palisades caught fire — the 100-year-old timbers burning rapidly — and in the smoke and confusion Te Rauaparaha's men were inside the pā before the defence could be reorganized. Of Kaiapoi's population of about 1000, only 200