Mobile operators in Thailand are to introduce special low cost mobile services for the country's poor following pressure from the government.

However, an executive at one mobile firm believes that the plan could put pressure on margins at smaller operators.

Thailand's relatively open mobile market with four main competitors means that its lowest call rates are already among the cheapest in the world, telecoms executives claim.

The cheapest currently available packages offer some calls for just $0.015 per minute.

Thana Thienachariya, an executive with second-ranked mobile operator Total Access Communication, told local media that government outlets will sell special Sim cards to low-income customers.

The new rates are to be decided in negotiations between the mobile operators and the government, he added.

Thailand's state-controlled fixed-line telephone operators may reduce their mobile interconnection fees to help support the cheaper rates.

Total Access is controlled by Norway's Telenor, which has a 73 per cent stake, and has more than 16 million subscribers.

Thailand's largest network operator, Advanced Info Service, had more than 23 million subscribers at the end of 2007.

Thienachariya said that the new local cost plan could have a negative impact on smaller operators that are less able to spread the additional support costs among a large number of users.

While Thailand has a relatively well-off middle class, particularly in urban areas, the majority of the country's population is poor. About half still earn their income from agriculture.