Thailand said today it would extend a security wall along its border with Malaysia in an apparent bid to curb a rising insurgency in the kingdom's Muslim-majority south.

Apart from reining in the three-year-violence that has claimed more than 1,800 lives, army-installed Prime Minister Surayud Chulanont said the new concrete wall would help prevent an influx of illegal workers into Thailand.

"The wall will help authorities check and prevent illegal immigrants from coming in and out of Thailand," Surayud told reporters. He was touring the restive south with Thailand's junta leader General Sonthi Boonyaratglin.

Thailand already has a three kilometre wall on its southern border between the Thai town of Sadao and the Malaysian town of Padang Besar.

Surayud said the government would extend the existing wall south by 27km to Yala, one of three restive southern provinces bordering Malaysia.

Since coming to power following a September coup that ousted former premier Thaksin Shinawatra, Surayud's government has adopted a more conciliatory approach in an effort to bring peace to the violence-torn south.

But shootings, bombings and arson attacks have continued to rattle the south, as a 68-year-old Muslim was shot dead on Sunday by suspected Islamic militants in a drive-by shooting while riding a motorcycle in Narathiwat.

Funds from Thai restaurants

The southern insurgency has strained the relationship between Thailand and Malaysia, with reports of insurgent training camps in Malaysia and claims that Thai restaurants there are funding the separatist movement.

Thailand also believes that militants behind the insurgency are abusing dual citizenship to escape across the border with Malaysia after committing attacks.

It has begun issuing fingerprint-embedded "smart" ID cards to 1.2 million residents of its Muslim-majority provinces in an effort to end the practice.

The residents are mostly ethnic Malay and Muslim, sharing more culturally with Muslim-majority Malaysia than with the rest of Buddhist Thailand.

The restive region was an independent sultanate annexed by mainly Buddhist Thailand in 1902. Separatist violence has erupted periodically ever since.