Gregory told the Herald on Sunday that a shared gate at the top of the driveway had been removed because Christian wanted to build a second gate 20m down the drive.
He claimed his neighbour did not want the hassle of driving through two gates to get to his home.
However, Christian said the second gate closer to his home was needed to make the driveway safe for his children.
"The whole issue was how to make our driveway safe with our two young kids," said Christian, father to Bronson, 2, and Pearce, 1.
"It's a shared drive and one day our little guy - he was about 1 at the time - made a sprint up the drive and I thought, 'Gosh, I've got no way to keep our drive safe'."
Evan Christian and his son Branson in the driveway of their Takapuna home. Photo / Frances Oliver
Christian, who is the chairman of Advantage Group, removed the shared gate on his property as the first step to installing a new private gate further down the driveway.
Gregory applied to the High Court to have the shared gate returned.
But the High Court ruling means Christian can go ahead with his original plans.
"I don't want to get off-side with anyone, especially not my neighbours, but when it comes to the safety of one's kids I will do anything I can to make sure they are safe," Christian said.
"We'll get the plans under way and we'll get that gate erected for the safety of our kids. My wife and I are very excited. It has been a difficult year," he said.
He added that he hoped the ruling would set a precedent for other parents wanting to keep their children safe on driveways.
Gregory, a former shareholder of glass supplier Metro GlassTech, said he was disappointed by the court's ruling.
"It's a gate, but it's disappointing because I can't believe that today people treat other people the way he has and with as little respect as he has," he said.
According to child injury prevention group SafeKids, a child is hospitalised with serious injuries after being struck by a car in a private driveway every two weeks in New Zealand. At least five children are killed each year in the same way.
Christian has joined forces with Safekids to raise awareness of the issue and help finance the organisation's submission for the new unitary plan to include driveway safety as part of new building permits.
General Manager of Safekids, Ann Weaver, said the organisation wanted to build community awareness around checking for children before driving, the limitations of a driver's field of view and the role that smart house design can play in reducing child injuries.
