Red-shirt activist Sombat Boonngam-anong and Nattawut Saikuar will lead a car mob rally on Sunday to keep up the pressure on Prime Minister Prayut Chan-o-cha ahead of the planned no-confidence debate in parliament.
The plan was the result of a meeting between Mr Sombat and Mr Nattawut over the planned protest on Sunday, which will be held in front of Thai PBS's office on Vibhavadi Rangsit Road at 2pm, Mr Sombat said on Facebook.
He said the car mob rally is planned ahead of the vote of no-confidence, which will be held in less than a month by the opposition in parliament against the government.
More rallies will be held during the debate, he said.
"It doesn't matter how the MPs vote, the people will cast their vote of no confidence. If you don't resign, this is what we'll do," he wrote, calling on Gen Prayut to step down.
The last car mob which took place on Aug 15 resulted in a clash between young demonstrators and riot police at Din Daeng intersection.
Separately, the police said 42 protesters have been arrested in relation to the violent clash at Din Daeng intersection on Sunday, from which 35 ping-pong bombs were seized along with several firearms.
Pol Maj Gen Piya Tawichai, deputy commissioner of the Metropolitan Police Bureau (MPB), said the protesters, who are a part of a group calling themselves "Mob Thalu Gas", are facing several charges, including unlawful gathering to incite chaos, violating the Emergency Decree and Covid-19 restrictions, and illegal possession of firearms.
He said police are also considering taking legal action against the parents of underage protesters for failing to control their children's behaviour, in accordance with the child protection law.
He said the parents face a maximum jail term of three months and/or a maximum fine of 30,000 baht.
The United Front of Thammasat and Demonstration group rallied outside the Justice Ministry at 9am on MOndy while the Thalugaz protest group said it planned to resume their protest at Din Daeng intersection at 5.30pm.
Sureerat Chiwarak, mother of protest leader Parit "Penguin" Chiwarak, renewed her call for her son to be transferred to Thammasat University Hospital for Covid-19 treatment.