Islamic extremists are planning a Tunisia-style massacre of tourists involving bombs placed under sunbeds, according to a German newspaper report citing Italian security sources.

German newspaper Bild reports that the jihadists planned to conceal themselves in tourist resorts posing as refreshment vendors.

They would detonate suicide belts and bombs placed under sunbeds at French, Italian and German resorts, German newspaper Bild reported.

Italy's Interior Ministry has denied the report, insisting there is no specific terror threat to the country's beaches.

Automatic rifles would also be used to gun down tourists, Bild reported, while bombs would be carefully buried in the sand near sunbeds to avoid detection.

It is understood that the south of France and the Costa del Sol were the main targets.

"This could be a new kind of terrorism," the newspaper quoted a senior German security source as saying, "holiday beaches cannot be protected."

The suspects are understood to be based in Senegal and are supporters of the Isil-allied jihadist sect Boko Haram, Bild reported.

As they regularly travel between Africa and Europe on business trips, they are already capable of embedding themselves in European resorts under the guise of selling snacks and souvenirs.

Seck Pouy, a police chief from Senegal, told Bild: "They want to strike Italian, French and Spanish beaches. They will exploit certain radicalized vendors who travel regularly between Italy and Senegal, apparently for work.”