Tamaki was speaking to adoring followers who had packed into the Rotorua Energy Events Centre for the church's annual conference.
The site will include a massive groundfloor church auditorium, recording studios, and a performing arts and science centre.
A model showed the complex would house a boxing gym, bookshop, atrium, cafe, early childhood centre, three schools and a university as well as a library.
"You get to see the finished product before you actually get to build it," Tamaki said.
He reassured devotees about the size of the development, saying "it's bigger than it looks".
"This is a gift from God."
And Tamaki said the church intended to expand beyond the Druce Rd site in Wiri, and that neighbouring properties could be bought if the church raised enough money.
"Once upon a time we didn't have a stage, we only had a dream," said Tamaki.
At the conference last night, Tamaki unveiled plans with a multimedia presentation and model of the new complex.
The evening featured references to "the promised land", interspersed with karaoke lyrics on a big screen. Beneath the biblical lyrics, copyright logos reminded parishioners who owned the hymn. Other entertainment included 10 dancing pastors, dressed in black, one of whom sang "I got the flow that you see on TV".
Among the faithful was Hamilton single mum Roimata Topi.
She waited eagerly in the events centre lobby with her "church family" of friends from Destiny's Hamilton branch.
"We all come together in unity, from across the nation," she told the Herald on Sunday.
Topi said Destiny's teachings and leadership made her happy and at peace. She joined the church 10 years ago but said this weekend's conference was especially exciting.
Destiny Church is selling its Mt Wellington headquarters, valued at $5 million, to finance the new city. It will rely on donations from members to pay for the rest.
Spokeswoman Janine Cardno said the church was also restructuring its finances and had deregistered several charities recently.
Tamaki and wife Hannah also took out new mortgages on two of their three homes in April.