Residents of the Silom business district held a brief rally in front of the Indian mission in Soi Sukhumvit to give moral support to Satish Sehgal.
The group said it planned to submit a letter to Indian Ambassador to Thailand Harsh Vardhan Shringla, asking the mission to protect the rights and liberty of Seghal.
The Centre for Maintaining Peace and Order (CMPO) decided on Monday to deport Sehgal for joining the PDRC, alleging he led protesters to besiege several government offices to pressure Prime Minister Yingluck Shinawatra to resign.
Seghal, who has been living in Thailand for more than 50 years but still holds an Indian passport, was an advisor to many former ministers, including those in the administration run by former premier Thaksin Shinawatra, Yingluck's brother.
On January 22, the Thai government declared emergency in Bangkok and some nearby areas for two months to quell violent protests aimed at forcing Yingluck from office.