The former general manager and ex-security chief of Don Mueang airport have been cleared of any wrongdoing in relation to the incident in which an airport security guard tried to assault a Chinese tourist last month.

A report on the incident was tabled at the meeting of the Airports of Thailand Plc (AoT)'s board on Wednesday, according to a source at the company.

It concluded Wing Commander Suthirawat Suwanawat, the former general manager of Don Mueang airport, and the ex-security chief of the airport, had done nothing wrong, the source said, adding the pair was not involved in the incident.

The source said the incident happened at 10.27pm on Sept 27 and was not reported to the security staff's superiors because no one was hurt during the altercation.

Accordingly, the airport's executives were not aware of the incident so it was impossible for them to deal with the problem at the time it occurred, the source said.

Because the case has become a big issue and hindered international relations, the AoT needs to improve its internal process of reporting incidents in airports, the source said.

The two executives had been suspended from duty for 30 days after the incident.

Wg Cdr Suthirawat was made the general manager of Suvarnabhumi airport on Oct 1, but he has not been able to take up the new post while his suspension remains in effect, the source said, noting he was still working at the AoT's headquarters.

According to the source, the security chief of Don Mueang airport has been transferred to Chiang Mai airport to work in the same position.

Regarding the security guard at the centre of the altercation, the source said a panel has been set up to consider whether he committed a disciplinary violation, and no conclusion has been reached yet.

A decision is expected next month, the source said.

The incident happened inside Don Mueang airport's immigration zone, where the guard and the Chinese man argued before the guard shoved him and raised his hand, which looked as if he was about to hit the Chinese man in the face. The man dodged the slap before another security officer intervened. The incident was filmed and shared online.

Authorities said the incident happened after the tourist was denied entry at the airport. However, Chinese news website CGTN said it occurred after the traveller refused to pay a bribe.