A vault containing Prince's unreleased music has reportedly been drilled open.

According to ABC News affiliate KSTP-TV, only Prince had the code to access the vault, which was accessed by a spinning wheel, so the company had to call in locksmiths to drill through the lock and get the door open.

Sources told the outlet the bank had to move quickly to take inventory of the vault's contents because they are legally responsible for safeguarding and handling all of the 'Little Red Corvette' singer's assets.

Prince - who released 39 studio albums, as well as working on dozens of other musical projects - previously admitted he expected someone to release the tracks, most of which are believed to date back to the 1980s, one day.

He said in 2012: "One day, someone will release them. I don't know that I'll get to release them. There's just so many."

It is believed there is so much material in the vault, it would be possible to release a new Prince album every year for 100 years.

Susan Rogers, Prince's former recording engineer, said recently: "We could put out more work in a month than most people could do in a year or more."

Last week, Prince's sister Tyka Nelson filed legal documents stating her brother didn't leave a will.

She requested to open a probate case and ask a judge to appoint a "special administrator" - someone who is appointed when there is no ex ecutor named in a will - to oversee her brother's affairs.

She stated in her documents: "I do not know of the existence of a will and have no reason to believe that the decedent ex ecuted testamentary documents in any form."

Tyka herself requested Bremer Trust, National Association, to serve as the official administrator because they provided financial services to Prince for several years.