Nairobi MCAs are split over the nomination of NRMKe General Miguna Miguma for the Deputy Governor position.
Top Assembly leaders differed over the proposal for Miguna to take over from Polycarp Igathe.
In a press conference at City Hall on Thursday, ward representatives led by Majority Leader Abdi Guyo rejected the nomination saying the candidate is neither a Jubilee nor Nasa member.
He added that the lawyer still has serious issues with his citizenship.
"In the first place, the Governor has flouted the law. Our party's Constitution is very clear that he cannot nominate someone who is not a member of Jubilee," he said.
"The Governor did not consult us on the move. We will reject the nomination when it gets to the floor of the House."
Majority Chief Whip Mwaura Chege and Ngara MCA Chege Mwaura also dismissed the nomination.
"Miguna hapana, hata kama mimi ni msemaji wa serikali, huyo hapana (Miguna is not a good choice), " Chege said.
However, Nasa-affiliated members hailed the Governor for the nomination saying it came within the seven-day ultimatum they gave the county boss.
Minority Chief Whip Peter Imwatok said Sonko would have risked being taken to court had he not heeded the directive to nominate a DG.
Imwatok added, however, that the county chief should not be playing mind games with the Assembly by nominating someone the state has not cleared.
"We will not allow the Governor to bring us shenanigans. We hope the consultation he was talking about included Miguna`s clearance to be in the country," Imwatok said.
He added that the Assembly will not be part of a process that will see the nominee not certified by the government to serve city residents.
Karen MCA David Mberia termed Miguna the most suitable person for the position and said Nasa was not against his nomination.
Mberia added that the Governor is mandated by law to nominate whoever he wants for the position as long as the person is qualified.
"Miguna is more than qualified and most suited for this position," Mberia said.
Meanwhile, Speaker Beatrice Elachi has said she received the letter "in a wrong procedure" and has written to Sonko for correction.
Elachi explained that she received the letter from a "lawyer of the nominee as if we are in court".
This is not right because we are not in contention of anything," she told reporters on Thursday.
She added that the Political Parties Act does not allow the Governor to nominate a deputy who is not a member of Jubilee Party.
Miguna, who is in Canada, says he is not aware of the hullabaloo and terms the conversations "malicious distractions.