The Spanish foreign ministry has summoned France's ambassador after French farmers hijacked Spanish trucks at the border and drained their cargo of wine.

The farmers attacked several Spanish trucks on Monday at a toll barrier at Le Boulou in southern France in what they said was a protest against unfair competition.

"We are protecting our products" from cheap wine coming from Spain and Italy, Frederic Rouanet, the president of the Aude winemakers' union, told AFP, vowing to continue the protests.

The Spanish Federation of Freight Transportation, which represents truckers, said French police had allowed the demonstrators to "act with impunity".

In July, Madrid issued a similar protest after French farmers ransacked Spanish trucks carrying milk and meat.

French farmers have been furious over falling food prices, which they blame on foreign competition as well as supermarkets and distributors.