Documents released to the Otago Daily Times under the Official Information Act show bankers Justin Crane and wife Kirsty Mactaggart were the only party of 23 potential buyers in the past three years to make an offer for the Lake Hayes property.
Mr Crane is the managing director and global head of loans, syndication and distribution for the Standard Chartered Bank Singapore, and his wife is Fidelity International's Asia Pacific head of corporate finance and equity capital markets and corporate governance.
The couple have owned a Millbrook property since 2003.
Last month the ODT reported the OIO had granted consent to the couple to buy a freehold interest in about 8.95ha of land at Ellen Johnson Tce, Lake Hayes, and a share as tenants in common at 149ha at Marshall Ave, Lake Hayes, along with the homestead and associated buildings - described by the OIO as an ''historic and derelict woolshed and stables'' - for $2.5 million from Bruce Gemmell.
Additionally, Mr Gemmell, who acquired the property in November 2012 to on-sell it, entered into a boundary adjustment agreement with neighbouring landowner Samuel Strain, to enable the original access to the homestead, via a tree-lined avenue, to be reinstated.
The OIO decision said the couple planned a ''major restoration of, and additions to'' the homestead.
They also planned to carry out extensive landscaping, including funding restoration of adjoining wetlands, to enhance the ecological environment.
The property was marketed by Sotheby's International Realty, which received 23 direct inquiries.
''Despite this interest, and considerable due diligence being undertaken by three of these parties, no offers other than the applicant's were received,'' the decision said.
''According to Sotheby's, property developers were of the view that the existing resource consents were less than ideal and that there was little to no profitability in the development ...''
''Potential home buyers quickly lost interest due to substantial refurbishment costs, combined with the requirement for consents, Historic Places Trust approval, unknown quantities in the build and contamination issues relating to a sheep dip.''
The property was consented for a lodge and day spa, along with a bar-restaurant.
Landscape architects engaged by the couple reported the homestead and its surrounds had been neglected for about 10 years.
A 2005 conservation plan identified problems with rot and borer in the homestead, damage to the woolshed and substantial deterioration of the stables.
The application met 10 of the 28 relevant criteria, of which 11 were considered not relevant.
It failed to meet seven criteria, including the introduction of new technology or business skills to New Zealand; added market competition, greater efficiency or productivity, or enhanced domestic services; and the introduction of additional investment for development purposes.
The office, however, was satisfied the couple had demonstrated financial commitment to the investment, having paid the deposit on the $2.5 million investment, and spent ''a significant sum of money'' carrying out due diligence.
It also found the benefit to New Zealand criteria was satisfied through the creation of jobs as well as protecting or enhancing the historic homestead and associated buildings.
''In addition, the overseas investment is likely to result in other consequential benefits, such as the funding and facilitation of the restoration of a section of the Threepwood Wetland ... a habitat for threatened species of native fish and swamp birds, and for a number of endemic bird species and waterfowl.''
With regard to the creation of new job opportunities, or the retention of jobs, the OIO found the criteria met, with the applicant advising carpenters would work full-time on the project for 18 months, resulting in employment of those people to deal with that project and other jobs.
