They have elected a trial by jury - but the date is yet to be set.
Up to 50 firefighters fought the early morning blaze that spread across three shops, cut power and closed a main road.
The ceilings in Taupō Sushi and Hamills (an outdoor clothing and goods store) collapsed, and the blaze took crews from Taupō, Rotorua, Kinloch, Tokoroa, and Ngāruawāhia two hours to control.
Fire Emergency New Zealand was first alerted to the smell of smoke at 1.15am.