A proposed new deputy police and crime commissioner "failed to demonstrate an adequate knowledge and understanding" of the role, councillors said.
Labour councillor Sareda Dirir has been nominated by Cheshire Police and Crime Commissioner David Keane to become his £50,000-a-year deputy.
Members of the county's police and crime panel were not impressed by her performance in a confirmation hearing.
But she meets the "minimum standard", the advisory panel concluded.
Mr Keane is due to make a final decision about whether to appoint Ms Dirir next week.
Mr Keane said Ms Dirir was an "outstanding candidate".
In a letter proposing her for the position, he said she "exceeds the criteria set" because of her experience as a councillor, teacher and "freelance policy and communications advisor".
Cheshire's cross-party police and crime panel, which scrutinises the work of the police commissioner's office but cannot veto his decisions, questioned Ms Dirir in February.
She told the panel she was nominated to the post by Mr Keane after a recruitment process involving "one of the most gruelling interviews I've ever gone through".
After the meeting the chair of the panel, Conservative councillor Howard Murray, wrote to Mr Keane to say the panel was "disappointed that on a number of occasions she appeared unable to draw down from what she had learnt from her very varied career, and demonstrate how she would apply her experience".
He went on: "The panel were of the view that Cllr Dirir failed to demonstrate an adequate knowledge and understanding of the operation of the police service and the criminal justice system."
At the meeting, Ms Dirir did not directly answer questions on whether police should be armed, or issued with spit hoods, saying she did not want to make "public proclamations without being fully briefed".
Mr Murray also wrote that Ms Dirir "provided insufficient evidence that she would have the level of personal independence they would expect of a deputy commissioner".
Concerns were raised by the panel about the fact Ms Dirir's parents sit alongside police and crime commissioner David Keane in the Labour group on Warrington Council.
During the hearing, Conservative councillor Andrew Dawson claimed "people may think you only got the job because of the link the police commissioner has with your parents?"
Ms Dirir said that claim was "not respectful or appropriate".
Linda and Allin Dirir represent the same Penketh ward on Warrington Borough Council as Mr Keane, who also remains a Labour councillor.
Mr Keane said it "would not be appropriate" to comment on the claim.
Linda and Allin Dirir have not responded to BBC requests for comment.
Ms Dirir also told the panel she would not promise to step down from her £10,404-a-year role as a councillor in Salford, saying: "If appointed I may consider how much time I can dedicate to the role and my role as a councillor.
"I need to talk to my family and the residents of Salford."
Previous Conservative deputy police and crime commissioner Margaret Ollerenshaw was paid £22,500 for a three-day week.
Ms Dirir is due to work a five-day week.
The panel said that, "on balance", Ms Dirir meets the minimum standard to fulfil the role, and her "energy and passion will help her succeed".