Several groups of protesters including the United Front of Thammasat and Demonstration, Mokeluang Rimnam, ThaluWang and People's Movement for a Just Society (P-Move), began demonstrating at 5pm.
Protesters put up placards on the pedestrian bridge and sprayed messages on the road. They also staged a mock hanging from the pedestrian walkway in memory of the protesters who died during the demonstrations against the government led by former PM Abhisit Vejjajiva in 2010.
Protesters urged senators to listen to the people's voice and Pheu Thai Party to maintain its stance on forming a democratic government with Move Forward Party.
They also urged political parties and senators to stop thinking that amending the lese-majeste law aims to overthrow the monarchy, saying that it instead has the objective of seeking a fair and just solution for the country.
If Pheu Thai betrays the coalition, it will face punishment from the people, said political activist Thatchapong Kaedam, adding that the party should strictly adhere to its stance to escape conservative parties' schemes.
He added that former PM Thaksin Shinawatra and activists who fled Thailand to escape political charges had the right to return home, adding that all parties should respect the people's vote in a bid to prevent a repeat of the clashes between protesters and riot police at Din Daeng junction last year.
Somyot Pruksakasemsuk, the leader of 24 June Democracy group, said senators and the Constitutional Court should be blamed for the delay in forming a government.
He claimed that the delay could result in more than 100 billion baht of damage to the economy, adding that household debt could increase to 90% of Thailand's gross domestic product (GDP).
If people have 100 baht, they have to spend 90 baht of it on debt repayment, he said.
Protesters organised drumming and firework shows to demonstrate that they will continue demanding democracy. They also shouted “dictators must perish” and “long live democracy” before dispersing.
Protesters have vowed to hold a rally from Asok Montri junction to Ratchaprasong junction on Saturday at 5pm.