Breckland, Broadland and North Norfolk DCs, South Norfolk Council and Kings Lynn & West Norfolk BC told the committee that its figures were flawed, and did not reflect growth pressures or increased spending demands in education and social services.
Breckland deputy chief executive Tim Leader said: “It has been done the wrong way round - they have said their proposal is affordable and are now seeking a post-facto rationalisation of that.”
A committee spokesman said the finance officers’ move was “disappointing, but does not do anything to halt the process”.
The unusual step comes as the districts were due today to ask a High Court judge to halt the county unitary plans.
Meanwhile, papers disclosed to aggrieved Devon, Suffolk and Norfolk districts have revealed that committee members were worried by the basis of some decisions, in particular the removal of the Shotley peninsula from Suffolk into an Ipswich and Felixstowe unitary.
An unnamed committee member wrote in an email how he believed the peninsular had good “communication lines” to Ipswich and should be included in the new unitary.
But another said the claim could not be backed up. “If this is the quality of our evidence then we deserve to have our proposals shot down in flames,” the officer said.