The council intends to close the libraries in a bid to make £200m worth of cuts by 2020.
Ben Wallace, MP for Wyre and Preston North, raised a formal complaint against the council, saying that it has broken its requirement to provide a "comprehensive and efficient" service under the Public Libraries and Museums Act 1964, according to the Lancashire Evening Post.
Culture secretary Karen Bradley and libraries minister Rob Wilson have confirmed that the matter is now being treated as a formal complaint.
Wilson said: “As part of the process for consideration of the complaint, I have written to the leader of Lancashire County Council to notify her that we are treating representations received as a formal complaint. Officials will also be requesting from LCC all the relevant information regarding changes to the library services. This detail will be carefull considered and analysed by the department.
“There is no set timetable for the secretary of state to consider a complaint that a local authority may be failing to carry out its duties in accordance with the act. The timescale will vary and is dependant upon a number of factors including the complexity of issues to be addressed and the volume of detail to be analysed. All relevant detail will be carefully considered to enable the secretary of state to decide whether a local inquiry is necessary to resolve any real doubt about the council’s compliance with its statutory duty under the act."
Wallace said: “All along my concern has been for those communities across the county who will lose their libraries and I’m delighted that the department for culture, media and sport has decided to review this decision.”
The county council is standing by the proposals and has said it is ready to defend the plans.
Deputy leader of the county council county councillor David Borrow said: “We have carried out a great deal of detailed work to ensure our proposals for libraries fulfil the council’s statutory duty to provide a comprehensive and efficient library service, and I’m happy for them to be scrutinised by the secretary of state.
“The changes we are making will contribute towards the huge savings the council needs to make, while ensuring that people still have good access to library services through an extensive network across the county. A modern library service is about far more than providing books in buildings, and we are planning to invest in and extend the reach of our mobile libraries, and meet the increasing demand to access digital resources, to ensure the council continues to meet its statutory duties. I hope that our offer to help establish community-run libraries will add to what will already be a comprehensive network.”