The plan, revealed in public tender documents last month, aims to get around the biggest barrier in the way of such a system now - a lack of coordination among the telecoms and electronic payment companies.

Singapore also wants the convenience that millions of Japanese enjoy - to be able to tap their 'wallet phones' on wireless terminals to pay for train rides and snacks.

But while the telcos and the payment companies here are testing the same technology, rivalry has kept them from running a common trial for users across the board.

In separate trials launched in the past two months, EZ-Link paired up with StarHub, and Nets hooked up with SingTel to test a wireless technology called near-field communication (NFC), which allows future phones to be used like stored-value ez-link or Nets cards.

The rival companies' systems, however, cannot be used interchangeably - not until 2010 at the earliest. So the authorities have stepped in to ensure that the technology race does not leave users disconnected and inconvenienced.

The Infocomm Development Authority (IDA) is calling for experts to design a common system that can be used by everyone.

IDA's tender, which closes on Monday, requires the system to be accessible by a subscriber of any mobile phone operator here and holders of wallet phones sold here in future.

The technical details will be worked out over eight months, with a rollout of the system, possibly as early as next year.

Some industry insiders are already welcoming it. Said Mr Nicholas Lee, EZ-Link's senior vice-president of business and technology: 'We will get more users on board because a common system will give people more choices.'

The current efforts are not the first shot at jump-starting mobile payment here.

In 2001, the IDA and several infocomm firms set aside $20 million to run similar trials, but were let down by a lack of handsets and services that often tested users' patience. For example, they had to sign up with a service provider to buy tickets from one cinema, and learn another system if they visited another cinema chain.

Experts warn, however, that this problem might still occur - unless a common system like the IDA's does its job.

Research manager Janice Chong from analyst firm Frost & Sullivan said it was important to minimise confusion for people.

Convenience is key for many users like IT consultant Chan Chong Hung, 34, who said: 'If I don't have to withdraw and change a $50 note to take a train ride, then yes, a wallet phone may be useful.'

siewtha@sph.com.sg