His eight-party alliance together has 312 seats in parliament, but he needs at least 376 votes in a joint sitting of the bicameral legislature, which includes the 250-member upper house appointed during military rule.
Pita said talks with senators were being held and that they should not vote against the will of the people. "We're asking them to vote for democracy, for the majority, and to return normalcy to Thai politics, so we can finally move forward," he told orange-clad supporters on Sunday. Supporter Jaturong Soisri, 28, said the voting day "will decide where our future will lead. We have to unite together".