Mr Choi is the newest owner of Westridge House in Yarralumla, one of Canberra's oldest residential homes, which he bought this year for $6.05 million. At the time of the sale, the price and the name of owner were withheld.

Mr Choi has now spoken out about his reasons for buying the prominent historic home, which backs on to the Royal Canberra Golf Course and is beside Weston Park. But such is his concern about privacy that he turned down requests to have an identifying picture taken.

The Choi family moved from Korea to Sydney in 1986, where Mr Choi worked in the IT industry.

After less than two years, the family relocated to Canberra.

"I just took the family for a drive to Canberra just out of curiosity one day, didn't come for work or anything, it was just a day visit with my family," Mr Choi said.

"I fell in love with Canberra - it was love at first sight and I haven't left."

After working in the government and private sectors in the capital, Mr Choi turned his interest to the property industry.

"When I first arrived, Canberra felt like a small town, a small village or town but after I arrived, less than 10 years, I saw it start to grow rapidly in all areas," he said.

"The geographic location, between Sydney and Melbourne and Canberra being the capital city as well, I thought its future would be quite strong and should be a major city rather than a country town - that's how I felt, and that's when I decided to start investing."

That was 20 years ago.

"Canberra's a great place to raise your family, it has a great educational system and environment whereas Sydney is a bit hectic," he said

"I like the quiet and calm lifestyle compared to busy Sydney and Melbourne and it's much easier to get around."

The father of two adult children said he was a passive property investor and wanted to target "prime and unique properties in high growth areas".

Starting with "small" units in Sydney and Canberra, Mr Choi moved into investing in prime and high end homes in inner-south Canberra.  His latest buy is the 19,210 square metre block of Westridge House.

Mr Choi was not a registered bidder at the auction, where bidding went up to $5.9 million before being passed in. But he was approached after the auction by the agent, who knew of his interest in "unique" properties.

"I was privately offered and I couldn't refuse it because I thought it was such a good buy," he said.

"In fact, according to the recent sales date, there have been a few properties around the area that fetched more than Westridge House."

According to Domain data, 4 Ord Street in Forrest, a 1932 square-metre block, sold for $6.45 million in April via a letterbox drop. The sale was the highest residential sale in Forrest and the third highest in Canberra.

Also in the same suburb, 7 Tennyson Crescent sold for $6 million in October last year.

Mr Choi said not only did he look at the property market within inner south Canberra and saw it was "booming", but the property itself was a historic part of the capital.

"I loved the garden - the openness of the garden and location is second to none, privacy and versatility and it's a home of grand proportions and I thought it was a good future growth looking at its location and all the features," he said.

"The reason I bought and my motive stems from a typical investor mindset - I buy looking for capital in future gain and there's a lot of potential to the property."

Mr Choi said he had not decided what to do with the vacant property but was "considering options to showcase the history" of it.

The historic estate near Weston Park was built in 1928 for Charles Lane-Poole, then inspector-general of forests. It has five bedrooms, three bathrooms, a lift and space for eight cars. There are also three vehicle-sized workshops.

In 1975, it became the home of the CSIRO, which used it as a forestry and bushfire research facility. The CSIRO left the building in 2009.

The National Capital Authority changed the planning from "community facility" to residential, but specified that it must remain single residential only.

In 2010, the estate was put under the hammer and bought for $3.2 million by the heir to the Tattersalls gambling fortune, Vincent John Adams Flynn, who died in 2016. It's understood the estate was inherited by a third party who was not related to Dr Flynn in May 2016.