Selwyn generally advocated for Māori rights and was often a critic of the unjust and reckless land acquisition practices that led to the New Zealand Wars. However his support of the Invasion of the Waikato, where, as chaplain, he was frequently seen riding on horseback on the frontlines with the British and colonial forces, and his involvement in the burning of women and children at Rangiaowhia in 1864, damaged his and the church's relationship with Māori, which is still felt today.