The Office of the Ombudsman has stood by its decision to declare the appointment of Nattawut Saikuar to the cabinet as ethically inappropriate.
Ombudsman deputy secretary-general Raksagecha Chaechai said the office was not convinced by Prime Minister Yingluck Shinawatra's defence of her appointment of Mr Nattawut to the post of deputy agriculture minister.
After considering Ms Yingluck's clarification, he still did not feel the prime minister exercised enough prudence in appointing Mr Nattawut.
He said the agency based its decision on a Civil Court ruling that street protests by red shirts, of whom Mr Nattawut is co-leader, were unconstitutional.
Mr Nattawut is also a criminal suspect in a number of cases involving red-shirt rallies, several of which are being considered by public prosecutors.
"The prime minister has not taken into consideration Mr Nattawut's ethical appropriateness when making the appointment," Mr Raksagecha said.
He said the Office of the Ombudsman will submit its findings to the House of Representatives and the Senate to take further action against Ms Yingluck as permitted by the constitution.
On the appointment of Nalinee Taveesin as a PM's Office minister, Mr Raksagecha said Ms Yingluck made that decision at her own peril.
He said the office has found nothing against Ms Nalinee, even though she is on a US list of people sanctioned for alleged business dealings with the regime of Zimbabwe President Robert Mugabe.
"The prime minister should be mindful that the blacklisting of a cabinet member is likely to affect the country and the government's dignity as well as public confidence," Mr Raksagecha said.
Mr Raksagecha's comments come after Ms Yingluck sent a letter to the Office of the Ombudsman insisting she has the authority to vet the qualifications of cabinet members and will not review their appointments.
Mr Raksagecha said the agency's decision has nothing to do with speculation about an expected cabinet reshuffle.
He said the agency has also accepted a petition to investigate the brawling in parliament on May 30-31 when Democrats protested against the speaker's decision to move debate of the reconciliation bills to the top of the House's agenda.
He said the House's ethics committee will be asked to look into the matter and report its findings to the agency within 30 days.