Bosses believe their products will be less favoured by UK purchasers if they are forced to pay a premium on European products because of import tariffs.
They claim international wine producers like New Zealand, Australia and Chile, who have been backed by Wetherspoon chief and Brexiteer Tim Martin.
The publican warned European exporters they are at “extreme risk” because UK firms could easily alter their product lists to favour global free-trade agreements reached after Brexit.
Speaking to AFP, Cesare Cecchi, director of Italian firm Famiglia Cecchi wine cellar, said: “Clearly the level of taxation is a crucial element because if it increases the price of our wines too much, I mean European ones, they won’t be able to compete with other types of wine.
European wine makers are worried about post-Brexit trade
If prices increase because of tariffs European wines won't be able to compete
“Honestly, I am very concerned, above all because of the uncertainty.”
The Italian said firms “have to hope” Brussels’ key negotiators can reach a successful conclusion to trade talks with the UK Government.
Mr Cecchi added: “We have to hope that good common sense prevails.
“Don’t forget that the UK exports over two billion euros of spirits to Europe.”
Alex Canneti, of Berkmann Wine Cellars, a British wine wholesaler, also offered the same opinion, warning his European counterparts of their potential struggle.
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He said: “I warned the Italians, we may have bilateral treaties with Commonwealth countries like Australia, South Africa and New Zealand.
“That will be pretty quick after the two-year negotiations with Europe.”
Around 55 per cent of wine imported into the UK comes from the EU and neither side wants to jeopardise sales.
Last month, European trade body CEEV and the UK’s Wine & Spirit Trade Association(WSTA) joined forces to call for a transitional deal between the UK and EU to keep the wine trade flowing.
WSTA warned of “lorry parks” in the south-east of England if a deal to allow trade to keep flowing through customs is not sorted before Britain quits the EU, adding customs charges could jeopardise sales.
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European Council President Donald Tusk gestures to members of the media as he leaves 10 Downing street after talks with British Prime Minister Theresa May in central London
Jean-Marie Barillere, CEEV president, said: “There is no doubt the UK market is of utmost importance for EU wine producers.”
Ignacio Sanchez Recarte, CEEV general secretary, added: “The overall objective of the CEEV is to ensure that there will be no disruption of wine trade flows between the UK and the EU-27.”
WSTA chief executive Miles Beale agreed: “A phased leaving process will allow time to establish an EU free-trade agreement and to put in place the necessary systems and infrastructure.
“Failure to do so risks disruption to supply chains, chaos at UK ports, increases in costs for UK businesses and ultimately even higher prices for consumers.”