The PPP won the most number of seats in December's elections, securing 233 of the 480 seats in parliament, although several of its winning candidates were later disqualified.
If the court rules against the PPP, the party would have to halt all political activities while the case is forwarded to Thailand's constitutional court, which would decide whether to dissolve the party.
Even if the party is found guilty any of several charges, the case would still be considered by several other bodies until the higher court ruled whether it had to be dissolved.
On Thursday the PPP's secretary-general said the party planned to formally announce a six-party coalition government on Saturday after a meeting to discuss policies and the makeup of the cabinet.
"We believe we will get fair treatment in court, especially after giving our statements and evidence to counter the case," Surapong Suebwonglee told reporters.
"Our priority is to restore confidence of investors and create an atmosphere of stability," he said, adding the party planned to propose Samak Sundaravej, the leaders of the PPP, as the future prime minister.
Allegations of election violations arose after Thaksin Shinawatra, the deposed prime minister, was seen in PPP campaign videos despite being banned from Thai politics.
Al Jazeera's Selina Downes, reporting from Bangkok, said the PPP has been openly supporting Thaksin, taking over the old offices of his disbanded Thai Rak Thai party and using the same logo.
"Just about everything suggests it's Thai Rak Thai all over again," she said.
The Democrat Party, favoured by the Thai military, has accused the PPP of being a front for Thaksin's Thai Rak Thai party which was dissolved by court order for electoral fraud.
But despite coming in second in the polls, Abhisit Vejjajiva, the Democrat's leader, said the court should not overturn the election results.
"I don't think the election should be disqualified. The people did their job voting," he told a press conference on Thursday.