But numbers tell a different story.
At its peak in 2003, when Tamaki proclaimed Destiny would be "ruling the nation" within five years, Destiny had 19 churches across the country and attracted more than 10,000 supporters from those churches and others to a march on Parliament.
Destiny has enjoyed the fact that the media has repeatedly reported them to be much larger than they are, says a former senior church member. In fact, he claims, they never had much more than 5000 members - and today, Destiny churchgoers are estimated at fewer than 3000 regulars at 11 remaining congregations.
Some claim Destiny staged its conference in Rotorua because it couldn't fill the auditorium at the Mt Wellington headquarters in Auckland.
"Brian is very aware of crowd dynamics," said one former senior Destiny member. "He doesn't like speaking to half-full crowds.
"Much to the delight of Destiny Church, politicians have sought the support of Destiny because they assume the church to be much larger than it is. In fact it is a very small minority group that knows how to grab a headline."
Churches have closed in Porirua, Wanganui and Dunedin, worshippers have moved on, and some pastors departed after tiring of Tamaki's autocratic ways.
The senior pastors who remain have been educated in the scripture solely according to Destiny's patriarchal autocratic values.
The bank balances may still be in the black, but the former member believes Destiny is theologically bankrupt.
Publicly, mainstream Christian leaders shy away from pejorative descriptions, preferring to speak of a deep "uneasiness" about Destiny.
Mark Keown, a senior lecturer in theology at Laidlaw College, said: "The concern from people in theological education is the tendency toward isolation and ghettoisation. It's very much seeing the world through your own lens and other voices are treated with suspicion. They reinforce their own view of the Christian world."
Tamaki's 'my way or the highway' views have led to ridicule, as well as reverence. The Cardinal Hoani character from the movie Sione's Wedding 2, who preaches the gospel while moonlighting at night clubs, is an unmistakable Tamaki wind-up. And there is even a band called the Brian Tamaki Massacre, a reference to the 1978 Jonestown cult massacre.
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Tamaki Senior, 54, has always done things his way, ever since he emerged from pub bands in Tokoroa in the late 1970s to become a charismatic preacher in the Apostolic Church movement.
In 1998, the former forestry worker started his own Lake City church in Rotorua with just 20 members.
One churchgoer recalls Destiny members recruiting talent from other congregations with promises of perks like free music gear.
The 'gospel according to Brian' spread from Rotorua to Whakatane, to Whangarei and Nelson. It was then a broad church made up of many cultures. Vulnerable and underprivileged Maori in particular were attracted to the certainty of Tamaki's message.
But there have also been high achievers among his members.
Whangarei personal trainer Chris Blair was a Destiny Church member for three-and-a-half years. He left several years ago when he wanted a "bit of a change" and now attends Crossroads Community Church. But his two adult sons and many of his friends and colleagues still attend.
He says Destiny and Tamaki get an unfair rap from the press because he's fearless about speaking out on social issues. "If you go into any run-of-the-mill church and you get down to their core values, they will be very similar to Destiny's. There are people from a difficult background and from a very privileged background. I wouldn't have any qualms about my children going into it."
Some say Destiny has parallels with Maori prophets including TW Ratana (whose church held the Maori electorates for half a century) and Te Whiti. But venturing into politics, and establishing Maori culture at the heart of its teachings, has alienated other cultures.
"They isolated other ethnicities, which is one of the reasons membership has been declining," says a former member. "They are very focused on Maori culture."
Tamaki advanced what is commonly known as "prosperity theology" - whereby 10 per cent of every dollar earned is donated to the church, and conspicuous wealth is God's reward for his loyal servants' good works.
"It's taking the blessing that Christians hope for in eternity and bringing it into the present," says Keown.
But many people were offended by the Tamakis' customised car, the Harley Davidson, the $500,000 boat, and the $1.25 million Maraetai home. And in April, Brian and Hannah Tamaki returned from a holiday to Africa and the Middle East.
The church has around two dozen charities, with Pastor Hannah Tamaki, 51, an 'officer' on many of them.
And there are signs that the church's finances may be about to come in for closer scrutiny.
In the past few weeks, two of Destiny's largest charities, Destiny Church Rotorua and Destiny TV, have been deregistered by the Charities Commission for not filing annual returns.
Hayes Knight chartered accountants chairman Craig Fisher says when a charity is deregistered it is now "flagged" to the Inland Revenue Department. "It's quite likely that if the IRD wasn't already taking an interest in them, they will be now."
The Destiny charities that remain on the register provide only extracts from their financial statements to the Charities Commission, which Fisher says is unusual.
"By only showing extracts of their financial statements a reader is not able to get the complete picture. For example there is no disclosure of related parties and related entities which can be a very sensitive area."
Fisher says an independent audit is the best practice for large charities - and may soon be compulsory.
Without seeing full financial statements, says Fisher, there is no way of verifying the millions of dollars that Destiny claims to receive in donations every year.
A request for an interview with the Tamakis was declined by Destiny spokeswoman Janine Cardno. But she says the two charities have been deregistered as part of restructuring the church, and that summarised extracts of financial statements are standard practice.
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Destiny has a December 1 deadline to move into its new premises, a 4ha former factory site in Druce Rd.
Tamaki, with Hannah controlling the purse strings, has promised to spend tens of millions of dollars on the new City of God in Wiri, an impoverished South Auckland area brimming with churches and Christians.
In the streets surrounding Destiny's new home, Christian belief runs strong. But most are unaware there will soon be a new church in town.
An elderly Samoan gentleman smoking a cigarette on his front step tells how his his two children are ministers at the Samoan Assembly of God just up the road.
A young man who answers the door strumming on a guitar, humming a hymn, hasn't heard about Destiny. But he bids farewell with a 'God bless you'.
Next door Annette Toa lives with her two children. She has been a Christian her entire life, and even attended a Destiny service, but has a less than charitable view of its preachings.
"I don't really want him here because he is using people for their money. We were thinking about moving because of him. I think they are intimidating." Toa says she fell out with a Destiny Church-going friend after daring to criticise Tamaki, and worries about other mates who are still with the church.
"They love him like he's a dad," she says. "I hope when he is judged he gets what he deserves ... families are suffering enough."
But as Destiny prepares to move into the new premises, Tamaki has already laid down plans for the future of Destiny, with his third-born child Samuel being groomed to take over.
"The succession plan is to give it to the son Sam," says a former member.
Samuel, whose 30-year-old wife Kiri closely resembles his mother Hannah, runs the Church's Movement Youth Trust. Together they also run their own record company and talent agency.
Samuel led a clutch of his "Global Rule Records" artists, including Billz, Becs, V.O.T, Sophie, Hitman, Baby Nyce and The Cook Sisters in performing at the opening of the Destiny Church conference on Friday night. The Mt Wellington headquarters has a recording studio where the young Christian musicians record.
"Samuel is a passionate musician, a rap artist," says a friend. "He and his wife are gifted songwriters and performers. That's a contemporary expression of Christianity."
Their four children Rome, Heaven, Diamond and Paris, will attend the Destiny school, presumably go on to Destiny University, and will never be exposed to any other form of education.
Some believe what he is doing is dangerous. The former senior member says: "They consider themselves to be a kingdom church. Many churches are speaking about kingdom these days, but Brian ... is building an empire. He has presented it as if he is the Kingdom of Christ."
Pushing Destiny further away from mainstream culture may be worse still.
Keown says: "I think Brian Tamaki genuinely wants to help people find God, but he is locked in a particular theological framework that's very much based around a charismatic leader with a very strict autocratic understanding of the Christian faith, particularly around the view of money."
