The grape harvest, which is under way for early varieties in the Auckland and Gisborne regions, is expected to be smaller than usual.
The harvest is running about a fortnight behind last year due to wet and cool weather conditions during summer which slowed down the ripening process.
New Zealand Winegrowers estimates the harvest will be 300,000 tonnes this year - a fall of about 30,000 tonnes on last year.
Spokesperson John Barker says the weather has had a negative impact on horticultural crops across the country, including grapes.
He says a smaller harvest could hit growers in the pocket.
But Mr Barker says that a few weeks of warm and dry weather could significantly turn things around for the 2012 vintage.
He says a longer ripening gives more opportunity for the flavours to develop and the next six to eight weeks will be crucial.
Mr Barker says the harvest in Marlborough, where 70% of New Zealand's wine is produced, will begin in mid to late April.