Bangkok - A Thai appeals court upheld a libel conviction against former prime minister Samak Sundaravej Thursday and sentenced him to two years in jail but then released him on bail.

The verdict came after Samak lost his post as prime minister on September 9 when the Constitution Court found him guilty of illegal moonlighting by hosting television cooking shows while he was in office. It is illegal for sitting prime ministers to earn income from a second job.

Samak was released on 200,000-baht (5,885-dollar) bail because he is a long-standing public official and promised not to jump bail.

His attorney, Prachum Thongmee, said Samak would appeal the case to the Supreme Court.

Samak showed no emotion as the verdict was read and avoided reporters and a group of about 10 supporters who wanted to present him with flowers as he left the court.

The Bangkok South Criminal Court also found Samak friend Dusit Siriwan guilty of defaming former Bangkok deputy governor Samart Rajpolasidhi. Dusit was also sentenced to two years and released on 200,000-baht bail

Prachum said they planned to prove their innocence.

"Samak and his colleague had no intention to defame the deputy governor," Prachum said after they had posted bail.

The case concerns Samak and Dusit criticizing Samart during a television programme. Samart sued, claiming the criticism was not true. The court ruled Samak and Dusit were public figures and they should have known their opinions would carry weight with many people.

A criminal court ruled in Samart's favour on April 12, 2007, and the Bangkok South Criminal Court upheld that verdict Thursday. The appeal could take a couple of years to be resolved. (dpa)