By THE NATION
Kittipong Pansungnoen told reporters that some Korat activists were arranging travel to Bangkok while others had already arrived.
The group would not hold a parallel rally in Nakhon Ratchasima since they feared turbulence, he added.
The Korat activists were travelling in several small groups, as a single big group could be easily blocked by officials, said Kittipong.
He also warned that the prime minister should not overlook the power of youngsters, who would not give up until they reached their goal.
The protesters are demanding an end to government intimidation of critics, dissolution of Parliament, and a new Constitution.
Anti-government protesters plan to camp overnight at Thammasat University on Saturday and march to Government House on Sunday. The protest is set to be the largest since the 2014 coup led by current premier Prayut Chan-o-cha, drawing an expected 50,000 to 100,000 people.