Prince's family have filed a lawsuit against the hospital that treated his first opioid overdose.

Last week, it was announced by authorities in Minnesota that there would be no criminal charges surrounding the death of the 'Purple Rain' hitmaker, who passed away in April 2016 after an accidental fentanyl overdose at the age of 57.

But on Monday, the late star's family took legal action against Trinity Medical Centre, the Illinois hospital that treated the singer for an opioid overdose the week before his fatal incident.

According to the New York Times newspaper, Prince's family - who filed the suit under the name of a trustee, Michael A. Zimmer - allege in the documents that the singer received ''improper medical care'' when he arrived for treatment in the early hours of April 15 2016.

The lawsuit also claims that the 'Little Red Corvette' singer's death was a ''direct and proximate cause'' of the hospital failing to treat his overdose properly, as well as its failure to to investigate the cause and provide proper counselling.

Lawyers for Prince's family, George Loucas and John Goetz, said in a statement to the publication: ''What happened to Prince is happening to families across America. The family wishes through its investigation to shed light on this epidemic and how to better the fight to save lives. If Prince's death helps save lives, then all was not lost.''

The lawsuit names Trinity Medical Centre along with its parent companies, as well as Nicole F. Mancha, a doctor who provided Prince with care at the hospital, and an unidentified pharmacist or pharmacy employee ''that consulted'' in the care provided to Prince.

Prince's family is also suing pharmacy chain Walgreens for ''dispensing narcotic prescription medications'' to the singer for an invalid medical purpose.

The lawsuit comes after Carver County attorney Mark Metz declared the case into Prince's death officially closed.

He said in a statement: ''Despite the intensive law enforcement investigation, there is no reliable evidence showing how Prince obtained the counterfeit Vicodin laced with fentanyl, or who else may have had a role in delivering the counterfeit Vicodin to Prince.

''Therefore, without probable cause and no identified suspect, the Carver County Attorney's Office cannot file any criminal charges involving the death of Prince.

''There is no doubt that the actions of individuals around Prince will be criticised, questioned and judged in the days and weeks to come. But suspicions and innuendo are categorically insufficient to support any criminal charges.''