COLUMBIA, Mo. -- There's a nearly $600 million backlog of deferred maintenance on state buildings because of inadequate funding, Missouri Auditor Nicole Galloway said Thursday.

Years of funding shortfalls also meant state-owned offices and other buildings have not been inspected regularly as required by state law, she added, pointing to funding restrictions by Gov. Jay Nixon as part of the problem.

"Regular inspections are necessary to identify and address issues before they become problematic, which minimizes upkeep costs and ensures buildings are safe," Galloway said in a statement. "The longer maintenance is delayed, the more expensive those updates become, and that costs taxpayers more in the long run."

The Administration Office's Facilities Management, Design and Construction Division generally agreed with the criticisms in the audit and said it's working to inspect buildings.

The division's response also noted it will work with lawmakers, Nixon and his administration's Budget and Planning Division to address monetary needs, though it said such funding ultimately is out of its control.

Administration office spokeswoman Ryan Burns in an email said Nixon inherited a backlog of at least $735 million in deferred maintenance when he took office that he's since worked to reduce.

Burns also pointed to a recent bonding signed by Nixon that will reduce the backlog by another $142 million. The audit reviewed maintenance through June 20, 2015, which was before the bonding package went into effect.