David Irving, a Cable Bay Vineyards director, said the first shareholders had enjoyed their experience and were delighted for the new owners.
General manager Nathalie Hinds said Mr Petrou had worked at the property for some years.
"Loukas was involved from 2006 with designing and building the restaurant and winery which opened in 2007," she said.
Mr Culley said the 4.5ha Church Bay property above Matiatia Bay was well known for the chardonnay and syrah grown at the vineyard.
Sauvignon blanc and pinot grapes were brought from the South Island and processed on the Waiheke property at Nick Johnstone Drive near Oneroa.
The business employs 27 people. The restaurant seats 120 people and about 25 weddings are held there annually.
Robyn Jones, co-owner of the nearby Mudbrick Vineyard and Restaurant, said she and her husband Nick considered buying Cable Bay but ruled it out because it did not stack up financially.
"We thought we were better off just looking after Mudbrick," she said. "It's a big commitment."