Prime Minister Srettha Thavisin said he will not be distracted from his job by the ethics complaint senators have filed with the Constitutional Court and which could lead to his suspension.
The prime minister was questioned while on an official visit to Italy on Sunday.
A group of acting senators have complained to the charter court that he violated the code of ethics in the recent appointment of PM's Office Minister Pichit Chuenban.
Mr Srettha said the issue did not affect his concentration on working for the public interest.
"No, I won't lose my concentration. I have a team of working staff and we are confident in our innocence... But I do not want to elaborate ... it would be pressuring the Constitutional Court," the prime minister said.
Mr Srettha said he viewed checks on his government as normal and he respected such moves. His side would prepare an explanation to show his innocence.
Mr Pichit was formerly an adviser to Mr Srettha. But he was also previously former prime minister Thaksin Shinawatra's lawyer in the lunchbox bribe scandal, which raised questions about his eligibility to serve as a cabinet minister.
He served time in prison for contempt of court for attempted bribery when he represented Thaksin in a controversial land case back in 2008.
On June 25, 2008, the Supreme Court sentenced Pichit and two of his colleagues to six months in prison after they tried to bribe Supreme Court officials by handing them a lunchbox with a paper bag containing 2 million baht in cash a fortnight earlier.
All three represented Thaksin and his ex-wife Khunying Potjaman na Pombejra in the Ratchadaphisek land case, for which Thaksin was sentenced to two years in prison in 2008.
The Constitutional Court is expected to meet on Thursday to decide whether to accept the senators' ethics petition about Mr Srettha and Mr Pichit.