It says delays in appointing a permanent finance director to North Lincolnshire PCT because of the shake-up 'contributed to the difficulties of the PCT'.
The PCT saw its overspend spiral from£1m in 2005-06 to£5.6m in 2006-07. At one point in the last year it forecast a deficit of£14m.
District auditor Michael Newbury said there had been 'too much reliance on finance professionals to solve problems and this weakened the overall strength of its response to its problems'.
Despite involving stakeholders in its turnaround plan Mr Newbury said he remained 'extremely concerned' about the PCT's financial health.
'The scale and extent of the known risks that it faces will require significant board and managerial leadership,' he said.
The report says 'better than anticipated performance' was achieved through strong management action and the return of£4m of PCT money from the strategic health authority.
PCT chief executive Cathy Waters announced this month she was to step down from her post for health reasons following two recent operations.