 On 10 September 1869, he was camped at Tauranga-Taupo with 120 men when Te Kooti's force of about 280 mounted a pre-emptive strike against him.Te Kooti succeeded in capturing Tomoana's horses and much of his equipment, but was forced to retreat under heavy fire.On 25 September, Tomoana joined forces with Hohepa Tamamutu of Ngāti Tūwharetoa, and succeeded in driving Te Kooti from Te Ponanga near Lake Rotoaira.