Wildfire damage to Australia's Yarra Valley region has been estimated to affect more than 150 hectares of grapevines across 29 vineyards.

The affected area represented about 5% of the region's total vineyard plantings, but further damage from smoke taint has yet to be accounted for.

The Yarra Valley Wine Growers Association said the boutique Roundstone, Yarra Yarra and Calders wineries have been destroyed.

Unseasonably hot weather before the fires, as well as poor fruit setting conditions in some areas during spring, also means that some grape yields are up to 50% below expectations.

Sticks winery general manager Rob Dolan said his crush volume would be down by 80% this year, due to grape spoilage.

"Anything that's had bushfire on it or around it will probably have problems, both from the heat and the smoke," he said. "The smoke in the atmosphere is the big question ... later-ripening varieties are going to have some problems."