A partnership between a long-standing New Zealand business and a Chinese investor begins today.

Blue River Dairy has sold its Invercargill based sheep's milk and powder processing plant to the foreign interest.

Founder Keith Neylor says it's an investment.

"Next stages are going to be a little bit larger than what we've currently achieved, so hence we've called in a Chinese partner."

He says there's a much bigger market for sheep's milk powders in Asia than there is here.