But Guthrie, who made his fortune selling hi-fi goods, is defiant. "The objectors are always the most vocal, but there are a hell of a lot of people who are for the marina being built," Guthrie told the Herald on Sunday.
"The vast majority don't care one way or the other, or they are quite happy for it to go ahead."
About 800 people have lodged submissions, more than 550 in opposition.
Well-heeled critics of the plan include Waiheke Island residents Sir Peter Leitch and John Hawkesby.
Opponents claim it is a privatisation of water space that will mainly benefit wealthy boat owners. Berth leases ranging from $50,000 to $200,000 would make its backers even richer, they argue.
Sir Peter, the Mad Butcher, questions whether Matiatia Bay is the best place for such a development.
"I love the place and I love kayaking into the bay just the way it is because it is beautiful," he said.
"I am not against Waiheke getting a new marina but, like a lot of people, I don't want it ruining the gateway."
Guthrie said a number of investors had put down a "substantial amount" of money on deposits for berths. But he admitted they would lose out if the proposal was sunk.
"I have 40 people who have all put money towards it on the basis this would be coming off the cost of the berth," he said.
This artist's impression, above, shows the facelift the proposed marina would have on Matiatia Bay, top of page. John Hawkesby, right, is among its critics.
"This is non-refundable. If [the development is blocked] they kiss their money goodbye, so let's hope we win."
When the development was made public in 2011, it was proposed to be home to 45 berths. Guthrie said about 220 boat owners were interested in securing a berth.
While he expected some opposition, at the time he said the project should be given the green light as "at the end of the day, it's a very sensible thing to do".
He added it "would be really nice to have it built in my lifetime so I can get some benefit out of it".
Soon after Guthrie went public, environmental groups and some islanders voiced their concerns about how the development, which would involve dredging and land reclamation, might affect Waiheke Island.
Meanwhile, the developer has put his luxurious home on the island's northwest coast on the market.
The sprawling four-bedroom property - which neighbours the home of one of the development's main critics, John Hawkesby - boasts multiple living areas, an olive grove and a solar-heated infinity swimming pool.
Graham Guthrie.
It is believed to have a price tag of more than $7 million. Guthrie, however, insisted he was in no hurry to sell. "We are waiting for a Russian or Chinese buyer to come and tempt us with a heap of money," he said.
'I don't want to die knowing I could have done something'
John Hawkesby doesn't want to go to his grave knowing he didn't try his best to block plans for the proposed marina on his island paradise.
The proud Waiheke Islander and former TV news presenter is the public face of opposition to the mooted development on the island, home to the rich, the middle class and other residents doing their best to keep their hideaway as tranquil as possible.
Hawkesby helped local objectors raise about $115,000 to fight the Matiatia Bay proposals and expects about another $100,000 will be required to fund upcoming proceedings in the Environment Court.
"I feel really thrilled at the extent of our presentation and case," he says.
"It is as good, rational, professional and rooted in law as we can possibly make it.
"I don't want to die knowing, thinking I could have done better."
To raise further money for the fighting fund, Hawkesby has teamed up with musician Pat Urlich and Toi Gallery co-owner Sally Smith for an event called "Art for Art's Sake - Money for Matiatia's Sake", in Oneroa on October 7.
John Hawkesby is trying to block the plans for the marina development. Photo / Michael Craig
"If we lose in court on the basis of what we have done, we were never going to win," Hawkesby adds.
"When this is all over I am going into a cave somewhere on the island and disappear for a bit."
Trouble in paradise: The fight for Matiatia Bay
*Development to cost an estimated $10 million
*160 berths will be available
*Demand set to outnumber supply, with 250 boat owners keen on a berth
*Lease prices range from $50,000 to $200,000
*800 people have made submissions to the Environment Court, including more than 550 in opposition
*3000cu m of sediment will be dredged, and will be used to reclaim land required for a carpark
$215,000 is the expected legal bill for the anti-marina movement
Key dates:
*September 30: Pre-hearing conference for the Environment Court at Ostend, on Waiheke Island
*October 6: Environment Court hearing to begin. They are set to last three weeks
