The NACC decided not to press charges against the other 73 legislators including caretaker Prime Minister Yingluck Shinawatra.
The NACC was asked to consider a petition seeking impeachment of 383 politicians after the Constitution Court on Nov 20 ruled the draft charter amendment seeking to change the make-up of the Senate to a fully elected chamber violated Section 68, which prohibits attempts to overthrow the monarchy and unconstitutional efforts to seize power.
The anti-graft agency agreed late last month to pursue charges against former House speaker Somsak Kiatsuranon and Senate Speaker Nikhom Wairatpanich, who are among the 383 legislators, for their role in the passage of the amendment.
Of the 308 former MPS and senators who would face charges, 293 were involved in proposing the unconstitutional draft and voting to pass the first, second and third readings of it, while 15 others voted in some or all of the three readings but did not take part in proposing the draft, NACC member and spokesman Vicha Mahakhun said.
Mr Vicha said a nine-member committee voted 7-2 to dismiss impeachment requests for 73 other legislators including Ms Yingluck because most of them only voted to pass the bill in the third reading and were not involving in proposing it.
As a result, there was not sufficient evidence to indicate their wrongful acts and their privilege of casting votes could be protected under section 130 of the Constitution. Of the 73 legislators, eight did not have any role in the passage of the bill.
The 308 politicians are due to report to the NACC on Jan 15-17 to acknowledge the charges, Mr Vicha added.