County Hall is facing calls for an independent investigation after fresh revelations key decisions could have been made 'unlawfully' because of blunders over how projects were approved.
Norfolk County Council has been forced to halt proposals to increase parking ticket prices because of doubts over the legality of the way the hike was voted for.
It comes just days after the authority admitted decisions to approve a string of multi-million pound transport schemes were also flawed, due to a similar gaffe.
The revelations have caused opposition councillors to call for external auditors to be brought in to investigate the extent of the problems at Conservative-run County Hall.
Steve Morphew, Labour group leader, described the situation as "an absolute shambles".
The latest problems emerged after the council announced it was delaying plans to raise the cost of pay and display tickets and residents' parking permits in Norwich, Great Yarmouth and King's Lynn.
This is because the plans were initially approved by the Norfolk Parking Partnership Joint Committee - made up of councillors from County Hall and other district councillors - which voted to introduce them.
It has now emerged that - although councillors did not realise at the time - the council's constitution does not allow the committee to make such decisions.
Instead, it should only make 'recommendations', with actual approval coming from Martin Wilby, Norfolk County Council's cabinet member for highways, infrastructure and transport.
By not following the correct procedure, the council was vulnerable to legal challenge, and could potentially have had decisions overruled and schemes called into question.
The same procedural errors were recently identified in a series of multimillion pound decisions made by the Transport for Norwich Joint Committee - also made up of county, city and district councillors.
Councillors on that committee had 'agreed' multi-million pound schemes, such as the £6m revamp of St Stephens Street and changes to Grapes Hill in Norwich, when they did not have the power to do so.
While the same decisions would have been made, critics said it called the competence of the council into question.
The county council says the parking ticket decision is the only issue it has identified linked to the Norfolk Parking Partnership Joint Committee.
But in the wake of the discovery of the mistakes - exposed when councillors asked to "call in" recent decisions for scrutiny - council officers are checking if there have been any other similar errors involving other decisions.
A Norfolk County Council spokesman said: “The council’s governance team is carrying out a routine audit of all committees.
"If matters are identified that require further consideration, action will be taken to resolve them.”
But Mr Morphew said that did not go far enough.
"You can't just sweep an absolute shambles like this under the carpet or out of the way with a review," he added.
"The rules and processes are there so Norfolk can be confident their money is being raised, managed and spent with the correct authority and competently.
"When it so clearly hasn't, there needs to be an external audit investigation to ensure everything is properly accounted for.
"Decisions to spend millions of pounds have been made without authority.
"Whatever the review comes up with, we must make sure Norfolk can have confidence in those managing public money.'
Parking increase delay
The introduction of increases for on-street parking pay and display tickets and residents' parking permits in Norwich, Great Yarmouth and King's Lynn will be delayed due to the issues.
The Norfolk Parking Partnership (NPP) Joint Committee had voted, at the start of March, to increase them.
A Norfolk County Council spokesperson said: “Decisions regarding the setting of fees are an executive decision.
"A decision on parking price rises was called-in, but this could not be heard, because it was attributed in error to the parking partnership committee and not the cabinet member.
"An updated report and decision notice will be published in due course and that will enable a further call-in to be made.
“The decision cannot be implemented until the notice has been published, any call-in made and, if it is, a scrutiny discussion is held and a decision made on whether this needs to be referred to the cabinet member."
The price rises had been due to come into force as soon as possible, although the council said it would always have been later than April.
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