American businessman Bill Foley says he is buying Te Kairanga Wines.

The deal is subject to shareholder and Overseas Investment Office approval.

The price was not disclosed, but the winery was established more than 20 years ago and is the largest vineyard operator in Martinborough.

A 34 per cent stake in Te Kairanga was owned by Rangatira Ltd, a Wellington-based investment company. Te Kairanga's shares trade on the Unlisted exchange, and last changed hands there at 50c each on December 17, valuing the company at $4.3 million.

Foley Family Wines NZ, headed by Bruce Clugston, will take over the running of Te Kairanga. The company already owns Vavasour in Marlborough and Clifford Bay winery in the Awatere Valley.

Foley also owns luxury lodge Wharekauhau, near Te Kairanga.