WASHINGTON (AFP) - US authorities announced charges Thursday (July 13) against more than 400 people, many of them doctors and nurses, over health care scams worth US$1.3 billion (S$1.8 billion) including the wrongful prescription and distribution of opioids.

The Justice Department called it the largest ever enforcement action of its kind and said 120 of the 412 defendants had been charged with opioid-related crimes.

Providing details on some of the scams, Attorney General Jeff Sessions said a rehab clinic in Palm Beach, Florida, for instance, allegedly recruited opioid addicts with gift cards, visits to strip clubs and even drugs.

This allowed the clinic to bill for more than US$58 million in false treatment and tests, said Sessions.

And a clinic in Houston allegedly sold prescriptions for opioids in exchange for cash, with one doctor there giving out prescriptions for more than two million doses, Sessions said.

"While today is a historic day, the department's work is certainly not finished. In fact, it is just beginning," Sessions said.

The barely controlled pumping of hundreds of millions of doses of opioids into US communities during the past decade is blamed for a sharp surge in addiction and overdose deaths which totaled an estimated 60,000 last year.