The red-shirt United Front for Democracy against Dictatorship (UDD) is mobilising supporters nationwide to join the pro-government rally at Rajamangala National Stadium.
The group insisted it will not confront anti-government demonstrators spreading out around Bangkok. Instead the group says it will wait and see what happens.
UDD co-leader Jatuporn Prompan said yesterday more red-shirt supporters are travelling to Bangkok to join the rally.
"We won't lose," Mr Jatuporn said.
The group, mostly made up of supporters of ousted prime minister Thaksin Shinawatra, began efforts to back the embattled government of Prime Minister Yingluck Shinawatra several weeks ago.
Besides red-shirt supporters, Mr Jatuporn yesterday urged people who want a "democratic society" to join the UDD's rally.
He attacked anti-government protest leader and ex-Democrat MP Suthep Thaugsuban for sending thousands of rally-goers in groups across the city yesterday, from the Budget Bureau and military headquarters to state-owned TV channels.
Mr Jatuporn said these marches and rallies, especially the ones at Channel 3, Channel 5, Channel 7, Channel 9 and Channel 11, are attempts at intimidation.
Protesters have maintained they intended to make only friendly visits to the locations.
"Are these visits also attempts to threaten media workers?" he asked in reference to a comment from Mr Suthep, who once alleged that red-shirt rallies at media agencies were a threat to media crews.
Mr Jatuporn yesterday also called on police to ask the court to issue a warrant for the arrest of another ex-Democrat MP, Chumphon Chulasai, also a protest co-leader.
The call for his arrest arose from allegations that Mr Chumphon carried a weapon into parliament.