A private investigator has been hired to patrol public areas and report people playing music without paying licence fees.

Auckland designer Alex Webster told the Herald he was stunned to find he had been secretly filmed in his company's showroom earlier this year by an investigator acting for law firm James & Wells.

The investigator said in his report to the firm that he called at the office and showroom at 12.06pm on May 22.

"Alex Webster had pop star Beyonce singing Halo and indie band MGMT's Electric Feel on the MP3 player," the report said.

The law firm was working for the record industry copyright collection body Phonographic Performances New Zealand (PPNZ).

What do you think? Should you have to pay a licence fee to play music in an office or a shop?