The Fair Work Ombudsman has confirmed it is conducting an official investigation into The Local Shack after workers walked off the job last week.

The confirmation comes after issues with the business came to a head last week, with staff at the Mandurah store quitting en masse, citing complaints of understaffing and bullying by management.

The Local Shack. Credit:Marta Pascual Juanola

In response to the walk-off, a representative for The Local Shack took to social media to allege the business had never been investigated by Fair Work.

"Please Note that The Local Shack has never received a complaint or been investigated by fairwork nor any other court for alleged non-payment of overtime or bullying. No current nor former employee has ever made a complaint against bullying, or non-payment of overtime [sic]," they wrote.