The cash-strapped Port Authority — which doled out $85.7 million in overtime last year — has “no clear strategy” for reining in payroll costs, according to a scathing audit released yesterday.

The agency should cut overtime before it hikes tolls, said state Comptroller Thomas DiNapoli, who conducted the audit.

“Overtime flows like water,” said DiNapoli.

The PA promised to cut overtime by 20 percent in 2010, but only managed a meager 3 percent, DiNapoli found.

In one instance, PA police Sgt. Thomas Hoey, who works at La Guardia Airport, earned $153,530 in OT in 2009 — $45,652 more than his base salary of $107,878.