Some airlines and tour operators are continuing to confuse consumers by advertising incomplete prices on the net, claims the Trading Standards Institute.
This is despite the Office of Fair Trading (OFT) telling companies to ditch misleading adverts by 10 May.
Since then, the OFT has won a pledge from the majority of companies to comply with the law by the end of July.
But it says it will not hesitate to take court action against any that still refuse to toe the line.
The Trading Standards Institute (TSI) carried out a spot check on web adverts last week.
It found two examples of the problem, one from an airline and another from a leading tour operator offering a holiday to Turkey from £117 per person (£234 for two people).
But, on selecting the dates, the holiday summary four screens later showed a price of £358 for two, with a long list of supplements.
These included: fuel supplements of £80 per person; ‘late booking charge’ of £30 per person; an ‘adult supplement’ of £28 per person; air passenger duty (government tax) of £10 per person; air passenger levy of £10 per person.
TSI holiday and travel industry spokesman Bruce Treloar said: ‘This was just a snapshot of the current concerns for the consumer. But it just should not still be happening.’
Holiday Which? Editor Lorna Cowan said: ‘We believe the price you see should be the price you pay, and we welcome the new measures, hoping that consumers will find it easier to compare the price of flights and package holidays. Many no-frills airlines do have good deals (even after they add on ‘extras’), so why not be honest and up front about them in the first place?’