Suffolk County correction officials are grilling sex workers as they are booked into local jails about any past run-ins with accused Gilgo Beach serial killer Rex Heuermann.

So far, two current inmates have told the county sheriff’s office that they recorded conversations with the hulking accused killer while they were working as escorts.

Now, authorities are looking for more.

“While interviewing women through the Suffolk County Correctional Facility’s unique human trafficking unit we have already found two women who had previously had contact with Rex Heuermann when they were employed as sex workers prior to their incarceration,” Suffolk County Sheriff Errol Toulon said in a statement Monday.

“While these women both received calls from Heuerman they declined to take dates with him.

“We will continue to interview women in our custody to determine if we can find others who have had contact with him to further the investigation.”

The sheriff’s office would not reveal what Heuermann allegedly said in the recordings.

Heuermann, 59, is charged with the murders of three escorts whose bodies were found in Gilgo Beach in December 2010. He is the prime suspect in the death of a fourth — with the four women known as the “Gilgo Four.”

They are among 11 bodies found at the marshy site in 2010 and 2011 — most of the cases still unsolved.

Authorities said the married father of two, who remained unidentified for more than a decade, frequently solicited sex workers through Craigslist and other online channels.

State and county police have combed through Heuermann’s home in Massapequa Park since he was arrested outside his Midtown offices on July 13, bringing in a backhoe and cadaver-sniffing dogs.

Suffolk County Police Commissioner Rodney Harrison said Monday that cops uncovered a massive walk-in vault at the home where they believe the accused killer stored as many as 300 weapons.

Harrison said the search, which is expected to wrap up this week, has been “fruitful,” but has not uncovered evidence that any of the victims were killed inside the Heuermann home.

Officials in South Carolina and Las Vegas, where Heuermann owns a property and a timeshare, respectively, have said they are also trying to find any links between the suspect and any missing women.

Heuermann pleaded not guilty and is being held without bail.