State officials' refusal to hear civic groups and riverside communities over the controversial Chao Phraya riverside promenade project violates people's rights as well as the interim charter, academics and civil society actors say.
Since 1997, Thais have enjoyed the right to express opinions and be involved in decision-making procedures, said Prinya Thaewanarumitkul, Thammasat University's vice-rector and a public law professor.
He was speaking at a weekend event held by the River Assembly (RA) to raise public awareness about the 14km New Landmark of Thailand project planned for the banks of the river.
Public participation in large-scale, high-impact projects was enshrined in the 2007 charter's Section 67, he said.
The former constitution said projects that may seriously affect a community's environment, natural resources and health shall not be permitted unless the impacts have been studied and evaluated.
Furthermore, the procedure must be carried out by an independent body and include the views from those who stand to be affected.
However, regarding the river promenade, such a process has not really taken place, critics of the project argue.
According to several community leaders who spoke at the seminar, City Hall and the government, as well as representatives from two state universities asked to carry out a feasibility study on the project, were informing residents of the project's features rather than asking their views.
Even under the junta's interim charter, such rights are protected under Section 4. They are also safeguarded by a 2015 Administrative Court ruling, Mr Prinya said.
Section 4 of the interim charter which says rights and liberties previously enjoyed by citizens under administrative conventions shall remain protected.
"Therefore, a real public hearing should be conducted ahead of any decision," the academic said. "If the government pushes ahead with the project before such process takes place, it will be violating the interim charter."
The project could be considered null and void in the future if it does not include people's views, he said, adding King Mongkut's Institute of Technology Ladkrabang and Khon Kaen University, in charge of conducting the study, should act impartially rather than advocate for the project.
The Bangkok Metropolitan Administration contracted the two universities to conduct the study along a 57km stretch of the Chao Phraya River's banks, from the Rama VII Bridge to Bangkok's outskirts.
They will also conduct public hearings and promote the project, particularly among people, such as those in Dusit district, who will be affected by the project.
Despite mounting opposition to the project since it was unveiled in December 2014, the government has pushed ahead regardless.
Construction is set to start in October, which means activists and communities have just a few more months to have their say.
As a last recourse, the RA -- a network formed on July 7 encompassing 61 non-profit organisations and business operators opposing the project -- could file a complaint with the Administrative Court, said Yossapon Boonsom, an architect who founded activist group Friends of the River.
"We think that many people remain unaware of the promenade's destructive impacts on the Chao Phraya River and will keep raising the public's awareness," he added.