Delegat Group's New Zealand harvest has fallen by more than a quarter but the wine company is still confident sales will rise this year.
Delegat's said it harvested nearly 27,000 tonnes of grapes for the 2015 season.
The New Zealand harvest has accounted for 25,000 tonnes, 26 percent lower than last year.
The company said that was partly due to higher than average yields the previous year and lower than average yields this year.
The wine producer said it was hit by cool weather over the flowering period and unseasonal late spring frost in Marlborough.
The Australian grape harvest, which accounts for just 6 percent of the group's harvest, rose 66 percent, to nearly 1,700 tonnes.
However, managing director Graeme Lord said that while the yields were down, the vintage was of excellent quality in all regions.
He said the company's inventories are well positioned, and still expects full-year sales to rise.