The golf resort will use its neighbouring farmland to create an additional nine golf holes and 42 home sites.
Work is likely to begin early next year and it is expected the new holes will be open for play in four summers.
Millbrook property and development manager Ben O'Malley said the new development would retain a rural, agrarian style.
The upper plateau will host 24 home sites and the lower slopes a further 18.
Mr O'Malley expects each section to fetch at least $1.5million.
By adding nine holes to its existing 27, it becomes the only New Zealand resort offering two 18-hole courses.
Millbrook's Japanese owners gained Overseas Investment Office approval to buy the 67ha Dalgleish Farm, west of its Coronet Nine course, in 2014.
In October, the Queenstown Lakes District Council approved an extension to the Millbrook Resort Zone, subject to appeals - but the only appeal is a minor one from Millbrook itself, likely to be resolved quickly.
Like the Coronet Nine, which opened in 2010, the extra nine holes have been designed by Arrowtown resident and former professional golfer Greg Turner and his Scotland-based associate, Scott Macpherson.
Much of the new nine will occupy ''perhaps the most spectacular landscape at Millbrook'', Mr Turner said.
More than 20ha will be retained as working farmland, while the historic woolshed will be rebuilt and relocated
to a paddock by Malaghans
Rd.
Parts of Mill Stream, which also runs through the Coronet Nine, will be widened, and an 1860s farmhouse will be kept and added to.
-By Philip Chandler
