The Pheu Thai Party wants the government to set up a new fact-finding commission on the political violence and crackdown of 2010, deputy spokesman Jirayu Huangsap said on Saturday.
Mr Jirayu said relatives of the red-shirt protesters killed and injured in the April and May 2010 events were unhappy with the report released last week by the Truth for Reconciliation Committee (TRC).
He said Pheu Thai MPs for more than 20 provinces in the North, Northeast and Central plains reported receiving complaints from red-shirts’ relatives that the TRC report was biased.
They were unhappy that the report placed heavy emphasis on the actions of the shadowy "men in black" and their links to the red shirts' United Front for Democracy against Dictatorship (UDD), said Mr Jirayu.
The TRC report has won support in other quarters for its conclusion that both the UDD and the Democrat-led government of the day had to accept responsibility for the way events played out.
The relatives wanted to send as many as 10,000 representatives to Bangkok to ask the TRC and the National Human Rights Committee to produce facts on the 2010 events, said Mr Jirayu.
The Pheu Thai MP for Bangkok said party members would discuss the demand for a new truth committee when they meet on Tuesday.
The new fact-finding panel would comprise members who are really impartial, he added.
Mr Jirayu also called on Democrat leader Abhisit Vejjajiva to refrain from making comments on the TRC report because as the prime minister serving in 2010, he had the most to gain or lose from it.
Tida Thawornseth, chairwoman of the UDD, said on Friday that the report was partial because some people who had "negative attitudes" toward the UDD had been appointed to the TRC subcommittee.
She insisted that the red shirts would not accept the report because it had been distorted, was not transparent, and it slandered the red shirts while creating justification for government forces to use violence to crack down on people.