Thailand's Supreme Court will rule Friday whether to ban the People Power Party for violating election laws. The PPP won general elections last month, but fell short of a majority.
A member of the Democrat Party, which came in second behind the PPP, brought the case Tuesday before the Supreme Court for Election Operations.
The Democrat candidate accused the PPP of being a front for deposed Prime Minister Thaksin Shinawatra's Thai Rak Thai (Thais love Thais) Party, which was dissolved after a September, 2006 military coup.
He argued that Mr. Thaksin and other leading members of the PPP were barred from politics for five years, but were being reelected by proxy.
Thailand's Election Commission is investigating 65 PPP winners for alleged electoral fraud. Three have been disqualified so far.
PPP officials say the investigation amounts to a dirty trick by Thaksin opponents to stop them from forming a government by a January 23 deadline.
The PPP victory was seen as a rejection of the generals and royalist establishment that tried to oust Mr. Thaksin from power.
Some information for this report was provided by AP and Reuters.