The trade should expect increasing numbers of class-action claims following disruption to holidays, but should not be intimidated into settling.

A leading industry lawyer told ABTA members at a seminar on extreme weather: “Class actions are increasingly being used to drum up claims and we are going to see much more advertising for claimants.”

Claire Mulligan, head of travel litigation at Plexus Law, said: “Do not be intimidated. Companies can be bullied into making an offer, but claims can be defended.”

Mulligan said a recent court judgment had described a letter to tour operators from one firm of solicitors as “intimidating”.

In an unrelated case illustrating the trend toward class-action suits, a US court-appointed administrator began a two-week advertising campaign in UK newspapers on Sunday encouraging British Airways and Virgin Atlantic passengers to claim refunds for fuel surcharges.

The refunds, amounting to £73.5 million, are in settlement of a class-action lawsuit in California after the airlines admitted colluding on fuel surcharges.

The ABTA seminar took place as Hurricane Bertha, forecast to miss the Caribbean, was declared the first major storm of the season.

Mulligan said: “Solicitors are advertising heavily and claims are increasing – not only for injuries, but for loss of a holiday. Yet we have a good record in defending claims. A claimant must prove negligence and the court will look at what was possible in the circumstances.”

A series of claims against operators followed 200 complaints by holidaymakers after Hurricane Wilma hit Cancun in October 2005. A class-action suit remains outstanding, but Mulligan said: “All have been defended successfully up to now.”

Experts have warned there is a 65% probability of up to five major hurricanes by the end of October, although weather consultant Norma Lynagh said: “Forecasts are inherently uncertain.”