Italy's total production is forecast at 41 million hectolitres, according to the organization, Coldiretti -- a near 15 percent fall on last year which it blamed on adverse weather conditions and the consequent prevalence of a number of plant diseases which affect vine yields.
In contrast, France's output is forecast by its ministry of agriculture at around 45 million hectolitres this year -- although definitive figures for both countries will not be available until the respective harvests are completed at the end of October or in early November.
In Italy, falls in output of up to 30 percent are expected in Sicily and Puglia, the regions hardest hit by what has been an unusually wet and relatively cold summer in many parts of Italy.
Average rainfall across the country in July was 73 percent higher than the average, a trend that both significantly reduced tourist spending and diluted the wine-producing potential of grapes.
Wet weather at the hottest time of year is particularly bad for grape producers because it encourages various forms of fungal rot.
Italy's wine sector is a significant player in the country's struggling economy. Its 200,000 producers employ 1.25 million people and have a combined turnover of €9.5 billion, half of which is raised from exports.