"Once again, thank you to all," the statement read.
Astle, who has been a mentor to some of the country's highest-profile chefs, including Michael Meredith and Simon Gault, told the Herald the closure was not related to Covid.
The decision to close Antoine's came following a personal matter, he said, but he would not reveal what that matter was.
Astle said he had not yet decided what was next for him professionally.
Parnell Business Association general manager Cheryl Adamson said the closure was an end of an era for Parnell.
"Antoine's was certainly one of the longest-standing businesses in the area, it was so quintessentially Parnell, it was housed in one of the converted villas and was a true representation of everything Parnell," Adamson said.
"It was the old-school fine dining, white tablecloths, silver service, all that attention to detail in terms of the food and the plating. You can easily say it set the trend for the entire restaurant scene in Parnell, if not most of Auckland."
Adamson said the closure of "the institution" was sad news.
"With it goes the end of an era."
Antoine's opened in Parnell in the 1970s and has survived a number of changes in the industry, but remained true to its style of cooking and hospitality.