According to New Zealand Winegrowers, sauvignon blanc made up almost 70 per cent of the 2011 grape harvest, with exports of all varieties worth $1.1 billion.
Sir George did not want to disclose what proportion of Villa Maria's production was sauvignon, but said it was below the industry average.
The industry had been dominated by a "sauvignon blanc mentality", he added.
"Our sauvignon blancs are great but sometimes [growth in the production of that variety] can be at the expense of other varieties you can do just as well."
Sir George said it would be great if sauvignon blanc could be reduced to 50 per cent of total production, which could help reduce bulk wine exports - a contentious subject in the industry.
"Bulk exports tend to be 99 per cent sauvignon blanc."
Bulk exports - wine shipped in huge plastic bladders for bottling overseas - have soared from less than 5 per cent of export volume in 2007 to about 40 per cent last year, raising concerns they could damage the brand image of New Zealand wine.
Questions have also been raised over whether this country, with its relatively high cost structure and long distances to export markets, can compete in the bulk space.
New Zealand Winegrowers chief executive Philip Gregan said this year's harvest was smaller than in past years and bulk exports would decline as a result.
He said New Zealand Winegrowers ran seminars overseas promoting wine varieties other than sauvignon blanc, including one last month in Hong Kong on pinot noir.