The Nairobi Health committee has opposed the reshuffling of Pumwani and Mbagathi hospital heads as regional balance was not considered.
Minority Whip Peter Imwatok accused chief officer Thomas Ogaro of executing "illegal postings" as only the Public Service Board has the powers.
He said Ogaro is a director who is acting without any appointment letter.
Imwatok said Dr Lazarus Omondi of Pumwani was told to hand over to Dr Catherine Mutinda while Dr Charles Wanyonyi of Mbagathi was told to hand over to Dr Loice Mutai.
Omondi has so far been deployed to Mama Lucy as a specialist, he said.
The Minority Whip further claimed medical superintendents from both hospitals were demoted because of the perception that they are affiliated to NASA.
"Demotions were done along tribal lines. This is against our country’s doctrine of equal employment opportunity and the Integrity Act," he said.
"The demoted medical superintendents do not have any disciplinary issues with their employer. They are being made to work under doctors who were previously their juniors, which is unacceptable."
Imwatok, who is Makongeni MCA, also claimed five departments at Pumwani Maternity Hospital are being headed by people from the same tribe.
The Health Committee further accused Ogaro of threatening the hospitals' CEO if they do not hand over, and harassing health workers in the county.
The committee demanded that all the professionals in the health sector be respected.
However, Ogaro dismissed the claims terming them "baseless and mere allegations without evidence".
"We carried out normal redeployment which the County Government Act has given us powers to do. It is not true that heads of departments are from the same tribe. We consider competence when deploying workers, not tribes," he said.