The ad includes a long checklist for applicants including excellent hygiene; event catering experience; excellent presentation and culinary skills; flexibility for adapting to family requests; honesty; reliability; and a great personality.
Although only Hart and wife Robyn still live at the family home, their daughter Gretchen, her husband Duncan Hawkesby and their children live next door and are said to be frequent visitors - with access via a gate in the fence.
Both families are passionate supporters of children's charity The Starship Foundation and are known to host events at the family home.
Hart - New Zealand's richest man worth an estimated $8.8billion - worked as a tow-truck driver and panelbeater before making his fortune in packaging and investments.
Hart's current executive chef, Peter Yeo, is leaving his role after six years.
He wouldn't comment on his time with the family because they liked to "keep out of the limelight" and he respected that.
Yeo said he was leaving to work for a project management firm that dealt with commercial kitchens.
Hart could not be contacted.