Al Jazeera's Selina Downes, reporting from Bangkok, said some believed that if convicted, Samak's party may jump at the opportunity to nominate a new candidate for prime minister to break the standoff with protesters who have been demanding his resignation for months.
But even if Samak is forced to resign, he will not be banned from standing as premier again and his ruling People Power party (PPP) has said it would re-elect him.
"We believe the court will give us justice but if the court rules otherwise, we will nominate Mr Samak as the prime minister again," Kudeb Saikrachang, a party spokesman, told the Reuters news agency.
"The majority of the PPP think that he is still qualified to be prime minister. He is no longer a TV show host and remains the party leader."
Samak had hosted a popular TV cooking show called Tasting and Complaining before becoming prime minister seven months ago.
|The protesters have been occupying the official grounds since August 26 [AFP]
He made a few appearances on the show - a mix of cooking and rants on various topics - after taking office, prompting a group of senators to petition the court on grounds that a prime minister was not allowed under the constitution to work with private companies.
The case is the latest embarrassment for Samak, who has not been able to enter his office at Government House in the capital, Bangkok, since anti-government protesters stormed the compound two weeks ago.
They continued their sit-in on Tuesday and say they will not leave until Samak resigns.