The suicide bid by a judge who shot himself in a Yala courtroom after handing down a ruling on Friday has sparked concerns over possible interference in the case.

Khanakorn Pianchana, a senior judge at the Yala provincial court, pulled out a pistol and shot himself at the end of a hearing on Friday afternoon, officials said. He was rushed to hospital where he underwent surgery for injuries said not to be life-threatening. The incident reportedly took place in a third-floor courtroom.

About 3.30pm, Suriyan Hongvilai, spokesman of the Office of the Judiciary, said Mr Khanakorn had apparently acted out of stress from personal issues.

He said the Office of the Judiciary would launch a fact-finding probe into the incident.

A 25-page statement Mr Khanakorn purportedly posted on Facebook on Friday before he shot himself was circulating on social media on Friday. The document was not visible on Facebook last night.

The document states the case he was hearing concerned national security and was related to secret association, conspiracy and gun-law offences.

The document allegedly described disagreements among senior judges over the case ruling, in which Mr Khanakorn reportedly decided to acquit all five defendants.

Messages reading "Return the ruling to the judges" and "Return justice to the people" were repeated three times in the document. The Court of Justice has neither confirmed nor denied the authenticity of the circulated document.

Future Forward Party secretary-general Piyabutr Saengkanokkul declared he did not believe the suicide attempt stemmed from stress.

He said Mr Khanakorn had been sending him information since early September, asking him to help make it the public.