Mobile phone operators will have to offer clients the option of putting a limit on their phone bills while abroad to avoid billing shocks.

According to new EU legislation, which entered into force yesterday, mobile phone operators are now obliged to offer their customers a monthly cut-off limit of €50.

They can also offer customers any other limit.

Customers will also start receiving a warning when they hit 80 per cent of the chosen limit.

For now people will have to make a deliberate choice to benefit from a cut-off limit but after July 1, customers will have the limit automatically set at €50.

According to the Commission, the new cut-off limit will guarantee more transparency and protection for consumers and it will ensure they will no longer face bill shocks for using data roaming services.

The action was prompted by some excessive cases, such as that of a German traveller in 2009 who downloaded a TV programme while roaming in France and faced a bill of €46,000 while a UK student was reported receiving a bill of almost €9,000 for data roaming during a single month while studying abroad.

Digital Agenda Commissioner Neelie Kroes yesterday said protection against data roaming bill shocks was a useful step towards building customers' confidence to use mobile networks to surf the internet when travelling around Europe.

"Such confidence is essential if people and businesses are to use the internet to its full potential."

The Malta Communications Authority is the regulator responsible in Malta to ensure that mobile phone operators comply with the rules on cut-off mechanisms for data roaming.

The EU Executive said that consumers can contact the national regulator in their member state where they reside if they encounter any problems or have concerns over these cut-off limits.