The government has ordered officials staffing checkpoints at its northern border with Thailand to stop going to the neighbouring country for meal breaks, a move aimed at tighter security.

Deputy Internal Security Minister Johari Baharum said stern action would be taken against officials flouting the rules and crossing the border to eat.

"They are on duty and are supposed to be in the country ... But we have staff, including uniformed employees, who go to Thailand without any documents just to eat and drink," he was quoted as saying by the Bernama news agency.

Johari said meal breaks in Thailand were leading to lax security measures, with officials giving special treatment to their Thai friends at checkpoints.

The decision comes in the wake of an incident earlier this month where a Malaysian border official was reportedly attacked by a gang of Thai nationals after he prevented one of them from entering the country.

The incident sparked concern over the ease with which the group had fled back to Thailand.

Malaysia and Thailand share a long border, with southern Thai Muslims sharing close cultural ties to their northern Malaysian counterparts.

No asylum seekers

Meanwhile, in another matter, Thailand's army chief denied reports that Muslims in the kingdom's insurgency-torn south were fleeing the bloodshed and seeking refuge in Malaysia.

His comments followed reports in New Straits Times newspaper that a group of Thai Muslims who last week apparently fled to Malaysia to escape the separatist violence had returned to Thailand.

"The Royal Thai Army has checked with Malaysia and did not find that anybody had fled to Malaysia to seek asylum," said General Sonthi Boonyaratglin, who led the Sept 19 coup which ousted premier Thaksin Shinawatra.

"So, this appears to be rumours spread by those with malicious intention," said Sonthi, himself a Muslim.

The official Bernama news agency reported Friday that 20 Thais from the Muslim-majority south had fled across the border into Malaysia to escape "military pressure".

However Sonthi dismissed such reports as "groundless," and accused local politicians of interfering with the situation in the south and starting rumours that people had fled.