ALMOST a quarter of Victoria's 740 small and medium-sized wineries are on the brink of oblivion.

That is the grim outcome of a new survey which found the industry's woes have put 1000 jobs and $857 million of rural economic activity at risk.

The survey commissioned by the Victorian Wine Industry Association found the global economic downturn had left scores of wineries unviable.

Chief executive Joanne Butterworth-Gray said the VWIA was "astounded" by the survey's outcome.

"An average of 20 per cent of businesses across the micro, small and medium categories are currently not profitable and therefore undecided whether they will stay in the industry," Ms Butterworth-Gray said.

"Victoria's wine story is about the diversity of those small businesses. We're at risk of losing 20 per cent of what makes us interesting."

She said the most vulnerable regions were emerging areas such as the King Valley and Gippsland.

"They are highly dependent on tourism and are very vulnerable if there isn't on-going investment in tourism and marketing activity," she said.

The survey concluded that if the economic downturn continues and the marginal wineries leave the industry, "almost 1000 full-time jobs will be lost and an estimated $857 million will be lost from the economy of rural and regional Victoria".

However, the heads of regional winery associations disputed the relevance of the survey to their own regions.

Gippsland Grapegrowers and Winemakers Association immediate past president Gary Surman said the region had several advantages in its favour, including the fact most growers didn't need to buy water.

"A lot of small operators do it for the lifestyle and even if they prove to be uneconomic by all the indicators, they may still want to keep going."

Heathcote Winegrowers Association chief executive Henry Screen disputed the survey's claim that 43 full-time-equivalent jobs and $24 million of economic activity in his region were at risk.

"I really struggle to see where those numbers come from, certainly in the context of Heathcote," Mr Screen said.

A spokesman for Regional Development Minister Jacinta Allan said the Government was doing what it could to raise the profile of, and open new markets for, Victorian wineries.