BRUSSELS - MORE than half of Europe's airlines may be forced to close their websites next year if they continue to mislead customers, an EU consumer affairs watchdog says.

An investigation by the European Commission (EC) to be published today and obtained by Reuters says 'over 50 per cent of all websites showed irregularities, in particular relating to price indications, contract terms and clarity of proposed conditions'.

'Companies will be contacted by authorities and asked to provide clarification or change their practices in four months,' the report says. 'Those who fail to do so could face legal action leading to fines or closure of their websites.'

The BBC says the investigation looked at 400 websites.

The results do not identify any airlines in particular, but the European Union's Executive Commission intends to 'publish a list of companies concerned' in four months' time.

Last month, Spain's consumer rights watchdog said it had found misleading information in seven of 12 airline ticket websites including Ryanair - Europe's biggest low-cost airline - and Spanish carriers Vueling, Iberia and Spainair.

'Ryanair and those other companies in the Spanish investigation are on our radar,' an EC source told Reuters.

The UK's Office of Fair Trading has also already taken action against 13 airlines for leaving taxes, fuel fees and other charges off their advertised prices, the BBC reported.

The Brussels investigation focused on unfair pricing, hidden charges and terms and conditions not translated properly.

The following are some of the misleading practices:

The ticket price is first shown without airport taxes and additional fees.

Offers promising tickets for free or at a low price, but such tickets are unavailable to the consumer who wants to buy.

Tick boxes for insurance or additional services are set to 'yes' by default, trapping the consumer into buying unwanted items.

General terms and conditions are not provided in the language version used by the consumer during booking procedure - or not available at all in any language.

No information is given about the rights and procedures of cancellation, transferability and ability to change dates.

REUTERS