Sajid Javid has ordered a review into "allegations of failures in financial management and governance" at Northamptonshire County Council.
On his first full day as the newly re-titled Secretary of State for Housing, Communities and Local Government, he commissioned an independent inspection to better understand whether the authority is complying with its legal requirements over value for money.
Mr Javid said: "My decision to appoint an inspector is not taken lightly. I hope it sends a strong signal that robust processes are in place to investigate allegations of failures in financial management and governance in local government."
Service users are not expected to experience any disruption during the investigation.
Council leader Heather Smith said: "We welcome the announcement that the Government will be conducting a best value inspection in Northamptonshire.
"We have been very clear with senior Government ministers and civil servants about the issues facing the county and the growing financial pressures we are facing.
"This announcement means they will be coming to the county to assess the situation for themselves and be able to see how we have continued to deliver public services in an ever challenging financial context.
"We have been fully open and transparent with the Government about our situation and have been direct in our request for assistance.
"We have also been clear that our proposed funding settlement from them includes no recognition of the pressures we face with the escalating cost of, and demand for, adult social care and children's services respectively.
"We look forward to the next stage of the conversation that this inspection will necessitate."
In a written ministerial statement issued on Tuesday, Mr Javid said publicly available budget documents were among those under the spotlight.
He said: "For some time there have been concerns about financial management and governance at Northamptonshire County Council, and in recent months a number of reports have been published, which have led me to question whether the authority is failing to comply with its best value duty.
"I have asked the inspector to report findings to me by 16 March 2018, or such later date as the inspector agrees with me."
Mr Javid said he could not provide further detail while investigations were ongoing.