Mobile number portability is unlikely to bring big gains for any operators but it will keep all of them on their toes as they strive to guard against customer defections, say industry executives.

AIS, DTAC and True Move say network size and subscriber totals have nothing to do with the mobile number portability (MNP).

"MNP represents another step in the evolution of the Thai mobile industry. It's just an alternative service," said Somchai Lertsuthiwong, executive vice-president for marketing of Advanced Info Service, the market leader.

Suphachai Chearavanont, the president and CEO of True Corporation, agreed that the group's mobile unit True Move saw no reason to expect significant number of customers to switch to its network once MNP becomes available.

However, industry experts believe operators could see a significant impact, especially from customers disconnecting their service. More importantly, number portability would allow numbering resources to be used more efficiently.

Number portability allows consumers to take their wireless numbers with them when they switch mobile operators.

The result is expected to increase competition and maximise customer satisfaction. More importantly, it is necessary for the protection of consumers as customers have the opportunity to select providers without having to factor in the inconvenience of changing numbers.

The MNP regulations of the National Telecommunications Commission (NTC) came into force last week, and operators have been given three months to fine-tune their networks and establish a clearing house to accommodate the changes.

Mr Suphachai said MNP was a double-edged sword, leaving operators either an opportunity to gain new subscribers or potential to lose customers.

He said he supported the idea, but True Move required an additional 12 months to prepare its servers and operating system to be ready for service.

He also said True Move preferred the NTC to host the clearing house for transparency, and each operator would invest in the system. But operators should be allowed to claim part of the costs as justifiable against their universal service obligation (USO).

Thana Thienachariya, chief commercial officer of DTAC, said the local mobile industry was "competitive enough" with or without MNP.