Buyers are said to be showing "hot" interest in snapping up Sir John Key's glamorous $23 million former home, but a legal objection by a mystery buyer must first be cleared before any sale can proceed.
The former prime minister and his wife Bronagh sold the Parnell mansion in 2017 to Chinese citizen Lianzhong Chen for $23.5m.
Now it is back on sale with the marketing tagline "fit for royalty".
However, land records show a trust called Awatea Custodians has lodged a caveat on the home.
The caveat is a legal tool preventing its sale until the caveat is removed.
Awatea Custodian's caveat says the trust has an interest in the Parnell home because it signed an agreement to buy it from current owner Chen last October.
The caveat section declaring the trust's interest states: "Agreement for Sale and Purchase dated 21/10/2022 between registered owner Lianzhong Chen as vendor and the Caveator Awatea Custodians Limited as purchaser".
The mystery adds to the intrigue surrounding a home that became one of New Zealand's most famous during Key's tenure on the ninth floor of the Beehive.
Key not only used the mansion as a setting for political get-togethers, but his son Max also made regular social media posts from within its walls.
The sparkling pool, in particular, became instantly recognisable as the backdrop for Max's many music videos and viral photos of his famous dad.
Key told the Herald his family has fond memories of the house.
"We had over 15 years of very enjoyable living in the home and we wish the vendor the best for a successful sale," he said.
New marketing by selling agent, Yi Wei Tang from Suburban Realty, trumpets the home's celebrity status, stating: "Former Prime Minister's mansion".
"New Zealand's most prestigious address ... Parnell was once home to the former Prime Minister John Key."
The home has "hosted politicians, international states people and even royalty - in sumptuous style", the advertising reads.
It boasts seven bedrooms, six bathrooms and comes on a 1753sq/m block.
It also has a gym, theatre, wine cellar, pool and spa and manicured gardens.
"The enormous main living room is majestic with 5-metre-high stud heights and soaring windows that fill the area with natural light."
Tang said she brokered the original 2017 sale from Key to Chen, with the Keys continuing to live in it until 2019.
After 2019, Chen visited the home many times and "loved" it.
Chen - who also owns a Remuera home - had plans to immigrate to New Zealand with his family at the time, Tang said.
But incredibly, he was never able to live in the mega-mansion despite paying $23.5m for it, according to Tang.
When the Covid pandemic hit in 2020, Chinese citizen Chen was unable to fly into New Zealand and has not returned since, she said.
With increasing business commitments in China and ongoing border restrictions last year, he decided to sell, she said.
Tang then brokered a sale to a New Zealand resident in October last year.
That new buyer spent six months living in the Parnell home but ultimately the sale fell through because they had trouble with their financing, Tang claims.
She claims the buyer is the one who placed a caveat on the home and that the caveat will be removed soon.
A lawyer for Awatea Custodians trust - which took out the caveat - said he cannot comment.
In addition to the lawyer, another person is named as a director of the trust on Companies Office records.
According to documents with the Companies Office, that person has listed two addresses against their name, including a modest $1.6m Greenlane home and a Henderson townhouse that recently sold for just over $800,000.
Lawyer William McCartney says that in general caveats are used to protect a person's belief that they have an interest in a property.
"So if a purchaser believes she has a valid agreement for sale and purchase, she can lodge a caveat to stop the land being transferred to anyone else," he said.
If it is determined that legally a person lodging a caveat has a "valid interest" in a property, then "the caveat remains until either the parties resolve it by agreement between themselves, or the court determines the dispute after a full trial".
"If there is demonstrable urgency, a full trial might take place within months of the caveat hearing. If there is no urgency, it might be a year or more after a caveat hearing," McCartney said.
An owner of land with a caveat against it can still make a contract to sell their property but they cannot complete the transfer.
"The agreement for sale and purchase in that circumstance would usually require the vendor to have the caveat removed and the land transferred within a fixed period of time," McCartney said.
"If the caveat is not removed, the agreement for sale and purchase will usually come to an end. Depending on what the agreement actually says."
Tang, meanwhile, said interest from buyers is running hot, with a number of them requesting viewings.
She said the home's Parnell location, its stunning high ceilings and features and its celebrity status as the Keys' former home are among its appeals.
It also has a renter living in it at the moment with the grounds and home being kept in great condition, she says.
"I took the photographs [of the home] four weeks ago, it is beautiful, you can see," she said.
Her comments come after the Parnell home made headlines in 2021 when it appeared to be sitting neglected and uninhabited, with neighbours fearing it was bringing down the "feel" of one of the city's poshest streets.
Grime appeared on the home's once immaculately kept walls at the time, while the garden was unkempt with autumn leaves piling against the entry gates.
One nearby resident said she felt like sending her son to trim the verge and tidy the fence line.
Another said he was concerned by the state of the ghost house.
"We don't want the best house in the street going backwards, it is a bad example for everyone," the man said.
But Tang said the home did have a caretaker living in it at the time, but they "obviously didn't do a good job" looking after the house.
"I mean [the] inside was fine, but outside was really messy at that time."
The circumstances around the death are being treated as unexplained.