A dramatic increase in area under vine in New Zealand's Marlborough wine region has put a serious strain on winemaking infrastructure this season, leaving some wondering if soaring grape prices of recent years have peaked.

For the past 10 years, Marlborough grapes, especially sauvignon blanc, have been in huge demand as wineries sought to capitalise on the rising international thirst for NZ wine.

The latest figures show that Marlborough now has 22,277 hectares in vines - a staggering increase of 12,000ha in less than five years.

Not all have begun bearing fruit, but many did come into production this year.

With ideal growing conditions, a mild winter and a long, hot summer, a bumper crop followed, resulting in a literal bottleneck in a bottle industry.

For the first time in many years, supply exceeded demand and those reliant on the spot market experienced a rollercoaster ride.