Mr Rames, a member of the Democrat Party's legal team, said one of the allegations by Mr Ruangkrai was against party chief adviser Chuan Leekpai, a former prime minister.
Mr Ruangkrai had petitioned the NACC to investigate Mr Chuan's assets and particularly some 200 Buddha images, casting doubt on how he acquired them.
Mr Rames said Mr Ruangkrai should have made a thorough check before filing a complaint and placing an unnecessary burden on the NACC.
Mr Chuan was known for his clean political record, adherence to the law, his righteousness and honesty, he said.
"From now on I will wage legal war against Mr Ruangkrai. The party's legal team will ask former MPs he has filed complainst against to sign a letter giving them power of attorney to file a defamation lawsuit in their home provinces to protect their reputation," Mr Rames said.