The regulations stipulate fines starting at about $280 for sales operations carried out without cash registers, a large sum relative to local incomes.
Leaders of several opposition groups participated in the rally, a local news agency said.
"You are fighting for your small incomes," leader of the Rightist Opposition party David Gamkrelidze said addressing the protesters. "The current authorities want to take even this away from you."
He said the opposition would attempt to make small business the core of the Georgian economy, and demand that the government create necessary conditions for this.
Similar rallies were held Wednesday in other Georgian cities. Clashes with police broke out during a rally in the city of Samtredia in western Georgia, as protestors attempted to block traffic.
Meanwhile, Georgian Finance Minister Alexey Aleksishvili said the authorities had not yet conducted inspections of cash registers, but that the government's position on the issue remained unchanged.
