Oamaru-based former All Black Ian Hurst, his brother Douglas and two business partners are developing the plans after completing the purchase of a more than 20ha block of land on Main South Rd, near East Taieri.
Mr Hurst, who is a director of Hurst Lifecare and has developed other aged-care facilities around New Zealand, said the cost of building the facility, should it gain resource consent and go ahead as planned, would be tens of millions of dollars.
Like most of the company's other aged-care facilities it would use the ''continuum of care'' model.
''So we will be seeking to put in care beds, a rest-home hospital and dementia [facilities] and to provide accommodation for independent living in the form of apartments and villas,'' he said.
It was too early to say how many residents the facility would provide space for, but it would be a ''substantial number''.
He also could not say when construction might start, but it would begin the process of applying for resource consent and drawing up plans next year.
''It's too difficult at this stage to put timelines on that; there are so many variables and so many issues that need to be resolved and so many approvals that need to be gained.''
Given the ''extensive'' nature of the project, he expected the resource consent process would be a lengthy one.
He and his business partners were really happy with the ''delightful'' piece of land they acquired after the sale process was completed about two weeks ago.
''It provides an opportunity to create quite a rural-flavoured development with spacious areas and it's got a very nice gradient for the elderly.
''It gives us an enormous amount of scope to make an expansive development there on 20-odd hectares.''
It was also ''as well as one can be'' unaffected by the flood plain on the Taieri, which was important given its location.
If the development went ahead, it would be great for Mosgiel and Dunedin, he said.
''With all our developments we endeavour to use local business people and trades.
''I'm sure there will be some positive ramifications for Mosgiel and Dunedin because they are big capital cost projects.''
The site, which included a homestead, was mostly used for grazing animals and would continue to do so ''until such time as we are in a position to break ground''.
Mosgiel Taieri Community Board chairwoman Sarah Nitis said the development would be ''fabulous'' for local tradespeople.
It would also continue the trend of rapid population growth on the Taieri, which was positive for the local economy, Mrs Nitis said.
However, it was important the Dunedin City Council invested in Mosgiel's infrastructure to match the growth.
''Infrastructure, especially around transport and water and waste is nearing capacity around Mosgiel and it's time for some reinvestment,'' Mrs Nitis said.
The fact the land was no longer being used as a residential subdivision open to everyone also raised the possibility that more land should be opened up on the Taieri for development.
If the project went ahead, it would join other aged-care facilities in Mosgiel, the largest of which include Chatsford, which has 320 residents, Brooklands Village, Birchleigh Residential Care Centre and Taieri Court.
According to Metro Reality's listing and a video advertising the site, it was bought by previous owner Gary Pearson in the 1970s and it was now being sold by his four sons.
The land had already been pre-approved for a residential subdivision and was only 1km from Mosgiel and 10 minutes from Dunedin.
