The family of the late rock star Prince is suing a doctor who prescribed pain pills for him, saying he failed to treat him for opiate addiction and therefore bears responsibility for his death.

Prince Rogers Nelson, 57, died of an accidental overdose of fentanyl April 15, 2016.

Authorities say Dr Michael Schulenberg admitted prescribing a different opioid to Prince in the days before he died, oxycodone, under his bodyguard’s name to protect the musician’s privacy.

Schulenberg has disputed that, although he paid $US30,000 ($41,000) to settle a federal civil violation alleging the drug was prescribed illegally.

The lawsuit filed in Hennepin County District Court this week alleges Schulenberg and others had “an opportunity and duty during the weeks before Prince’s death to diagnose and treat Prince’s opioid addiction, and to prevent his death. They failed to do so.”

Schulenberg’s lawyer, Paul Peterson, said on Friday they believed the lawsuit had no merit.

According to the complaint, which was first reported by US TV network ABC, Prince’s family seeks unspecified damages of more than $US50,000.

A lawyer for Prince’s six surviving siblings said on Friday the new lawsuit in the musician’s home state of Minnesota would eventually replace a lawsuit they filed in April in Illinois to beat a legal deadline.

Authorities say Prince probably did not know he was taking the dangerous drug fentanyl when he took counterfeit pills laced with fentanyl that looked like a generic version of the painkiller Vicodin.

The source of those pills remains unknown and no one has been charged in Prince’s death.