Some local wineries that are also a great place for lunch...

Vineyard, cellar door and restaurant in Bannockburn. About twenty five minutes drive from the Hill House, Turn right onto Hwy 6 continue on past Cromwell to Bannockburn.  http://www.mtdifficulty.co.nz/

Carrick Winery

Vineyard, cellar door and restaurant in Bannockburn. http://www.carrick.co.nz/

Quartz Reef

Vineyard, cellar door and restaurant in Bannockburn http://www.quartzreef.co.nz/

Northburn Station

Vineyard,  cellar door  and restaurant near Bendigo, opposite side of the river from the Hill House and close to Cromwell.  http://www.northburn.co.nz/

Further Information

These links http://www.otagowine.com/ , http://www.nzwine.com/wineries/central-otago/, will take you to more detailed and comprehensive information about the local wine region.