New Zealand wineries may be well aware of the dangers of oversupply, but a new study has revealed they also need to keep a close eye on their debt levels.

With the 2008 vintage producing a bumper crop that led to fears of a wine glut, the third annual Deloitte financial benchmarking survey for that vintage – released this week – unsurprisingly focused on oversupply concerns.

Local worries about wine overproduction are nothing new, according to a leading UK wine expert who has been importing and judging New Zealand wine for more than three decades.

John Avery was chief judge at the New Zealand Wine Show in 1978 and was back in New Zealand this week to serve as an international judge at the latest Air New Zealand Wine Awards.

Mr Avery has been importing New Zealand wines into the UK since the early seventies and told NBR calls to limit production following two bumper harvest had a familiar ring to them.