SingTel and its Bridge Alliance group of telecom operators on Monday launched Asia's first flat-fee data roaming service across 11 regions, promising lower costs for people on the move.

For $48 a month, a SingTel user can download 15 megabytes (MB) of data, the equivalent of 300 e-mail messages or 150 webpages, while overseas. This will help slash their bills by up to 90 per cent.

Travellers from the other 10 operators in Malaysia, Hong Kong and India, for example, can also log on to SingTel's network at the discounted rates.

Any additional usage is charged at prevailing rates, which work out to about $24 a megabyte, when a user is roaming in Hong Kong, for example.

But Bridge Alliance chairman Lim Chuan Poh said most users chalk up less than 5MB of data overseas.

Mr Lim, who is also SingTel's chief executive officer for international, said the flat-rate makes it easy for people to gauge how much they might spend overseas.

Until now, users are charged a roaming fee for logging on as a 'guest' to a network belonging to a foreign operator. This is on top of the usual rates it charges.

But operators worldwide have lately been rethinking how to get more roaming users onboard.

European mobile giant Vodafone, for example, has signed up more than 12 million customers for its Passport service, which lets them make phone calls overseas at the same rates as when they are at home.

The service, available in 13 countries, is said to have shaken the mobile industry, where turfs have in the past been divided up geographically.