Officially called the People Assembly Reforming Thailand (Part), the body has been formed to push for a "just, secure and happy society".
Its formation is seen by observers as a snub to Prime Minister Yingluck Shinawatra's political reform initiative that kicked off in the absence of the opposition Democrat Party.
At the launch, a temporary 16-member committee was unveiled and the panel is expected to start its work next week.
It is headed by Banjerd Singkhaneti, dean of the Graduate School of Law at the National Institute of Development Administration (Nida); Khomsan Phokhong, a law lecturer at Sukhothai Thammathirat Open University; Pichai Rattanadilok Na Phuket, of Nida; Suriyasai Katasila, co-ordinator of the Green Politics Group; and Somkiat Pongpaiboon, a former core member of the People's Alliance for Democracy (PAD).
The current political crisis has been caused by the monopolisation of power by a group of people who violated the rule of law in pursuit of personal gains, according to a statement read out by Mr Banjerd. He said this group of people lack ethics in national administration, engage in abuse of natural resources and policy-oriented corruption and weaken the justice system.
Mr Banjerd said the current political system is dominated by "a political party driven by capitalism".
It has led to ultra-capitalist authoritarianism in the cloak of democracy.
A lack of input from the public and members of political parties have created an elected dictatorship in parliament.
The problems facing the country could not be solved by those in power as they are the root cause of the conflicts, Mr Banjerd said.
Instead, the public must come together to push for structural reforms.
The Part came to existence to accomplish this goal, Mr Banjerd said. It would campaign for reforms under the slogan "ending the gap, creating justice".
The principle behind the formation of the Part is to return power to the people, get rid of monopoly and ultra-capitalism and create a fair and happy society.
Mr Suriyasai said after the launch that the committee would meet on Sunday at Rangsit University to lay down the framework for its work.
An assembly would be organised soon to mark the 40th anniversary of the Oct 14 student uprising.
Representatives from 77 provinces would be invited to share their views about reforms.
He said the committee would also go on a tour to meet respected public figures, such as Prawase Wasi, to ask for their insights. The panel would also seek opinions from red-shirt leaders, such as Charan Dittha-apichai, and victims of political violence, such as Payao Akkahad, mother of a volunteer medic shot and killed during the mayhem in 2010.
Among the 45 groups were the People's Democratic Force to Overthrow Thaksinism (Pefot), which is rallying at Lumpini Park, Thai Spring, the multi-coloured shirts group, and the Siam Samakkhi group.
He said a team of advisers was also appointed to help the committee.
They include Pol Gen Vasit Dejkunjorn, founder of the Thai Spring movement, Sangsit Piriyarangsan, dean of the College of Social Innovation at Rangsit University, and ex-PAD member Pibhop Dhongchai.
Mr Pibhop said Sunday that the campaign had received a warm welcome from civic groups. However, hard work lies ahead for the campaign to gain acceptance from all concerned parties.
He said political reforms would take time and to make sure it materialises, the outcome of the reforms should be written into the constitution.
He said this would mean the rewrite of the entire charter.
Mr Pibhop said the government-sponsored charter amendments fail in addressing political reform.