(NZHerald) - New Zealand winemakers have been given a production warning in a new report by PricewaterhouseCoopers. The report, NZ Wine Insights, tells them to be cautious, lest they repeat the cycle that led a vast number of them into receivership over the past four years. The wine industry generates $1.2 billion of export receipts, but it's at the mercy of the weather and of unpredictable foreign exchange. "We support the general tenor of the PwC document, which is that things are improving and there's a growing sense of confidence but it's important the wine industry does not forget the glut of the past four years," said Philip Gregan, chief executive of NZ Winegrowers.