"Invermay", in Factory Rd, is under conditional offer.
Advertised online as a "unique Taieri lifestyle" option, the category 1 home was built in the 1860s.
PGG Wrightson real estate agent Roger Nicolson said there had been "good interest" in the property, and a conditional contract had been signed, subject to certain clauses.
Some rooms have been used as laboratories, and most are temperature controlled.
The labs, part of a more modern structure behind the historic home, were once part of University of Otago’s animal research school.
Other buildings include a hay barn, sheep yard and shearing shed, washdown bay and old boiler house.
"It would be great if someone with deep pockets was able to turn it into an animal sanctuary. That would be a beautiful turnaround," New Zealand Anti-Vivisection Society director Tara Jackson said.
The 4.2ha property is set among established grounds and trees, several of them on the Dunedin City Council significant trees register.
Homes New Zealand has estimated its value at $1.18 million to $1.23m.
Heritage New Zealand Pouhere Taonga’s website said Invermay had historic significance because of its connection to the Gow family, who were among one of the earliest and most prominent settlers on the Taieri Plain.
The use of the site as an agricultural research station had been mooted as early as 1949, and it was sold to the university in 1956.
The majority of research work had been undertaken nearby, to the east of the homestead, it said.
