The New Zealand Winegrowers chairman says the industry must learn from the mistakes of last year, when for the first time wine production exceeded demand.
The record crop of 285,000 tonnes of grapes was 39% up on the previous year.
Stuart Smith has told a conference in Napier that growers and companies this year accepted the challenge of bringing supply and demand back into balance.
He says that discipline needs to continue into next year and beyond, because wine is still being sold unprofitably.
Mr Smith says a harvest of 265,000 tonnes in 2010 would bring supply and demand back into balance.
Another wine industry leader is calling for thousands of hectares of grape vines in Marlborough to be pulled out, to protect the region's reputation for quality sauvignon blanc.
Jim Delegat from Delegat's Wines says excess production of sauvignon blanc, some of it of inferior quality, is damaging the image of New Zealand's flagship export wine.
Mr Delegat says up to 5,000 hectares of vines - a fifth of Marlborough's sauvignon blanc plantings - should be removed.