Mutua says he made the appointments in the best interests of Machakos people.
Machakos MCAs have faulted Governor Alfred Mutua for appointing into office executive committee members without the approval of the county assembly.
The county ministers were sworn in on Monday by Chief Magistrate Alfred Kibiru at the governor's office though the county assembly had not made a decision on their suitability.
MCAs including Majority Leader Mark Muendo, Justus Kiteng'u (Kivaa Ward) and Jeremiah Munguti (Muthetheni) said the process of appointing the executives was still in the assembly.
Speaking Sunday at a fundraiser at Kathiani AIC Church, the MCAs said Dr Mutua had misquoted the law to justify the appointments.
Mr Muendo said the assembly was guided by the County Assemblies Act, 2017 and not the 2012 parliamentary Act which Governor Mutua cited while making the appointments.
Mr Muendo said 21 sitting days had not lapsed since assembly started vetting the nominees as Governor Mutua claimed.
"Governor Mutua should follow the law. Nobody is above the law,” said Mr Muendo.
He said the assembly had an option of challenging the move in court, adding that the MCAs would not sit back and watch the executive misuse county resources.
The assembly had halted debate on the suitability of the nominees in order to await the verdict of the Supreme Court where Governor Mutua has appealed against the nullification of his election by the Court of Appeal.
Members feared that endorsing Governor Mutua's list of executive members could lead to misuse of county funds in the event that a fresh election is called.
While appointing the ministers, Governor Mutua said the assembly had failed in its duty to vet them.
He cited section 9 of the Public Appointments Act saying the members are deemed to have been approved after the expiry of 21 days from the date the governor submitted the names to the assembly.
Dr Mutua said he made the appointments in the best interests of Machakos people and in upholding the Constitution and the rule of law.
He observed that the assembly had rejected his initial five executives after which he submitted to the assembly another list of nominees.
He added that his actions were necessitated by the assembly's failure to debate on the report and interruptions seeking stoppage of the discussion of the same.
"In exercise of the powers conferred to me by Article 179(2)b as read together with Section 30 2 (d), (e) and 35 of the County Governments Act, 2012, I have appointed the seven as county executive committee members," said Dr Mutua.
The county executive members are Evelyn Mutie (Energy, Lands and Housing), Morris Aluanga (Roads, Transport and Public Works), Titus Nzeki (County Administration and Decentralised Units) while former county secretary Francis Mwaka will head the Trade docket.
Others are Kimeu Kimeu (Public Service), Urbanus Musyoka (Agriculture) and Lazarus Kivuva (Education).