A spokesman was unable to confirm a report that one Briton had died.

He said it was believed about 30 British people were involved.

Newspapers said the tourists were staying at the Grand Hotel Gardone on Lake Garda, near Brescia, northern Italy, when they fell ill at the weekend.

Reports said Geoffrey Appleyard, 71, from Evesham, Worcestershire, who was on holiday with his 74-year-old wife Jean, began complaining of stomach pains a few hours after dinner on Saturday night at the four-star hotel.

Paramedics were called and treated him, but he died in his room.

One health official said: "We think it was some fish that guests had eaten, but we are still working on all theories."

Stephen Anderson, British consul in Milan, was quoted as saying: "We have offered Mrs Appleyard assistance. It is too early to say if her husband's death is directly linked to the incident."