The health of yellow-shirt activist Veera Somkwamkid, who is imprisoned in Cambodia, is deteriorating, Democrat Party MP Panich Vikitsreth said on Wednesday.
Mr Panich, one of the seven Thais arrested by Cambodian troops on Dec 29 last year for illegal entry, said Mr Veera had a head injury, skin rashes and respiratory illness due to poor air circulation in his cell.
The MP said he had talked with the mothers of Mr Veera and his secretary Ratree Pipatanapaiboon, who is also detained in Phnom Penh. Both mothers were concerned for Mr Veera and Ms Ratree and wanted them to be released as soon as possible.
The quickest way to get them released was to petition the Cambodian monarch to grant the pair a royal pardon, he said.
Mr Panich said he hoped the case of Mr Veera and Ms Ratree would be treated similarly to the case of Thai engineer Sivarak Chutipong who was granted a royal pardon by Cambodia's King Norodom Sihamoni before serving the usual two-thirds of his sentence.
Mr Sivarak was found guilty of stealing the flight plan of former prime minister Thaksin Shinawatra ahead of his visit to Cambodia in 2009.
The Phnom Penh Municipal Court on Feb 1 jailed Mr Veera for eight years, and Ms Ratree for six years, after they were found guilty of illegal entry and espionage on Dec 29.