She will show prospective buyers the manor for a $400 fee, which she believed would separate out serious buyers.
It was something Real Estate Institute of New Zealand president Helen O'Sullivan had never seen before in a big sale. "I guess what they are aiming to do is avoiding too many tyre-kickers," she said.
"You are certainly only going to pay for a tour of the estate in the event that you are pretty serious about looking at it."
The home has furniture and ornaments collected from around the globe, insured for $2 million.
An outdoor garden party area sits alongside an African-themed retreat called the "safari room", featuring carvings and an antique Newman Brothers piano.
The formal living area includes sea vistas, an antique music box, a set of French lounge chairs that is one of five in the world, and a large dining table surrounded with paintings by US artist Chris Hopkins.
Ms Hignett said the sales campaign was targeting Asia and Europe.
Majestic mansion
• The $12 million asking price of the estate dubbed the Majestic Haven is thought to be among the biggest - if not the biggest - of its kind in Tauranga.
• The previous most expensive listing and sale for a residential property in the city on QV's records was a five-bedroom house in Mt Maunganui's Marine Parade, listed for $8.5m and sold for $7.9m in May 2007.
• The Majestic Haven includes a rare wind-up music box, a bedroom with an indoor balcony, and a "safari room'' with an antique piano