"There were more people joining the picnic on the streets than voters," said the former Democrat Party MP. The People's Democratic Reform Committee (PDRC) called for a "national picnic" day on the streets of Bangkok to express opposition to the election.
"The PDRC will try to end this game quickly because the government can no longer claim legitimacy. The poll is already over but the government remains stubborn," Mr Sathit said.
He criticised caretaker Prime Minister Yingluck Shinawatra for showing her "stupidity" by putting her ballot papers in the wrong boxes at a polling station in Bung Kum district.
He said caretaker Labour Minister Chalerm Yubamrung was wrong to declare that the Pheu Thai Party will win more than 260 seats in parliament because the Election Commission (EC) had already stated that the results will not be officially announced until Feb 23.
"I believe this election will become null and void," Mr Sathit said. "We're the voice of the majority who will protect democracy by going through reform before holding an election.