Plans to cap the cost of mobile roaming fees for consumers have run into trouble at the European Parliament. Following intensive lobbying by industry, MEPs are preparing to back a watered-down regulation that will force customers to "opt in" to benefit from tariff protection.

The parliament's rapporteur on roaming, Austrian MEP Paul Rubig, warned yesterday that forcing firms to switch 150 million roaming customers onto a proposed new tariff structure could cause chaos.

Instead, he has proposed an "opt-in" provision that will force all mobile customers to actively choose to be protected by the consumer protection tariff (Euro tariff). His amendment to the draft regulation is being supported by his own party, the European People's Party (EPP) - the largest group in the parliament.

It is also being supported by the liberal group, which combined with the EPP to support the amendment last week in the Internal Market and Consumer Protection Committee.

"I don't want to force people to accept a new tariff package. Consumers should have the right to opt in," Mr Rubig told The Irish Times. He said making consumers opt in would ensure customers who do not use roaming would not have to change their payment plans. People who use discount roaming packages could also choose to remain on them rather than adopt the new tariff.

His comments follow closely the line taken by mobile firms, which are lobbying MEPs in the run up to a vote on the regulation in May. A letter from Europe's biggest mobile firm, Vodafone, to MEPs, dated March 14th, warns that choosing an opt-out system would result in higher roaming bills.

Mobile phone firms have also warned they will be forced to increase domestic tariffs to compensate for lost roaming revenue if the regulation affects all users.

Under the draft regulation drawn up by EU commissioner Viviane Reding, customers would pay no more than 50 cent per minute for a call anywhere in the EU. She supports making the new Euro tariff mandatory unless consumers specifically opt out.

The EPP and liberal groups support for the opt-in system was criticised by the socialist group. Joseph Muscat, who sits on the parliament's internal market committee, accused them of a "drastic U-turn in favour of big business and against consumers' interest". It was a fudged proposal, he said.

Mr Rubig rejects the allegations of bias and says consumers need the right to choose.

Fine Gael MEP Simon Coveney also supports the EPP position, accusing the socialist group of "left wing paranoia" on the issue.

Several parliamentary committees are expected to vote over the next few weeks on the draft regulation before all MEPs vote on the measure in May.