The mother of a teenage worker who was killed when he fell from a worksite in the Perth CBD faced the men charged over the tragedy in court on Friday.

Contractor Valmont WA admitted to WorkSafe charges two years after 17-year-old Wesley Ballantine fell to his death while working at Perth's flagship H&M store.

The teenager was working as a steel fabricator for Industrial Construction Services and was on night shift at 4.30am installing a glass ceiling when he fell through a void in the roof of the internal atrium.

Regan Ballantine has spoken out after WorkSafe flagged it intends to prosecute two different construction companies following the death of her son Wesley Ballantine in 2017 at the H&M clothing store work site. Credit:Marta Pascual Juanola

He was rushed to Royal Perth Hospital but could not be saved.