A German-led campaign to boycott Spanish strawberries over environmental concerns has enraged farmers and Spain's right wing, forcing a German parliamentary delegation to suspend its work Monday.

The issue touches on increasingly-scarce water resources in the strawberry-growing heartlands of southern Spain where a regional government plan to legalise illegal berry farms has angered environmentalists and worried Brussels.

Spearheaded by German consumer group Campact, the campaign urges top German supermarkets like Lidl and Edeka not to stock strawberries grown in Huelva, a province in the southern Andalusia region which is Spain's biggest exporter of red fruits.

So far, its online petition has garnered more than 163,000 signatures.

This is "a harsh and unjustified attack on our agricultural sector" said the ASAJA farmers union, denouncing the boycott as an "attack on thousands of producers and their families who work hard all year round".

"This campaign is insidious and harmful to the entire strawberry and berry industry and its workers," said Interfresa, an association representing the Spanish strawberry industry.

"It shares false information and accuses the sector of serious misconduct and committing illegal actions."

Campact's campaign singles out a draft law introduced by the region's right-wing government to legalise illegal berry farms near Donana National Park, one of Europe's largest and fauna-rich wetlands.

If the bill passes, environmental groups say it could legitimise 1,500 hectares (3,700 acres) of crops, most of which are irrigated by illegal wells, which could jeopardise the future of this UNESCO-listed nature reserve that is currently threatened by desertification.

"If the Andalusian regional government has its way, even more water will now be used for strawberry cultivation," the campaign says, warning such a move would "destroy this fragile ecosystem" and urging consumers to stop buying "drought strawberries".

- 'Intolerable interference' -

The campaign drew an angry response from the right-wing opposition Popular Party (PP) which runs the region, which said the bill sought to update a 2014 law that regularised 9,000 hectares of illegal crops but left out several hundred farmers.

Strawberries from Huelva are facing "unfair attacks driven by ideological reasons", said the region's agriculture minister, accusing the left-wing central government of Prime Minister Pedro Sanchez of backing the German campaign.

On Monday, the controversy escalated with the arrival of a cross-party delegation of nine German lawmakers to discuss the implications of the ongoing drought in Spain and of the "illegal water extraction" in the Donana region.

This visit by German lawmakers who are "seeking to inspect our farmers' produce, notably of Spanish strawberries, is totally unacceptable," said Santiago Abascal, head of the far-right Vox which supports the legislation.

"It is interference that no decent government should tolerate."

- Climate change denial -

Sanchez, who is resolutely opposed to regularising the illegal farms, has constantly accused the PP and Vox of climate change denial and warned the Andalusian government about possible European sanctions if it pushes ahead.

With tensions high, the German delegation on Monday morning said it was suspending the visit, which had been due to end on Friday, in light of "the considerable political significance" that such topics had assumed "in recent days in light of the upcoming Spanish election".

The trip's purpose had been "to exchange expertise and gather information" on climate change and its consequences, with the delegation expressing hope to "continue this exchange in the future".

Interfresa figures show Huelva produces an annual 300,000 tonnes of strawberries, accounting for more than 90 percent of Spain's strawberry production, with the industry generating 100,000 direct jobs.

Germany is Spain's main export market for strawberries, with annual sales of an estimated 186 million euros ($200 million).

In early 2022, some 20 European supermarkets, among them Lidl, Aldi and Sainsbury's, called on the Andalusian government to shelve the controversial berry bill.