The building in Station Road, Bamber Bridge, is now just an administrative hub since it closed to the public a decade ago.
County Hall chiefs say the two-storey station - built in 1994 - is in need of an urgent upgrade to improve the working environment for those based there.
"The proposal will enable Lancashire Constabulary to fully utilise an under-used facility," says a planning report to South Ribble Council.
An application to carry out the work was this week approved by the council - even though next-door neighbours Network Rail claimed the work had already begun.
The plans are for improvements both externally and internally to bring the 28-year-old building up to date.
It no longer has a front counter where the public can report crime - that shut in 2012.
The custody suite has also been closed for several years, with prisoners now put in cells in the main police station at Preston.
LCC want to improve the lighting and CCTV outside the police station, as well as replace the boundary fencing and re-configure the car park to create a further 17 vehicle spaces.
Plans for improvements inside the building have not been made public because they are deemed to be "of a confidential nature."
The work outside will include replacing doors and windows to improve the "thermal resistance" of the property.
"The station no longer provides direct public access and is now used as an administrative hub," says the application report.
"The current custody unit is no longer used and has been empty for some."