More than 1700 New Zealand wines will be tested and judged as part of the 20th Air New Zealand Wine Awards at the North Harbour Stadium.

The wines are tasted by a panel of 21 judges and awarded a bronze, silver or gold medal. Top prizes are the 19 trophy awards up for grabs.

Judging began yesterday and will conclude tomorrow, with the medals to be announced on November 7 and trophies on November 11.

The chardonnay, sauvignon blanc and pinot noir categories had the most entries, and there's a new category for viognier, a speciality white wine.

Judge Sam Harrop, a New Zealander who lives in Britain, said the New Zealand wine industry had matured quickly in the 10 years he had been away. The quality of New Zealand wines was always consistent and now winemakers had to work on the complexity of their wines.

"I'm super impressed with this competition. The focus, professionalism and attention to detail is admirable," he said. "Consumers and producers can feel confident that the results are accurate."