The mother of a 15-year-old girl who suffered a major electric shock while walking near an exposed power cable next to construction of Sydney's light rail line on George Street has demanded the state government “get it together before someone is killed”.

Her call comes after a report found an exposed wire could have posed a danger in the four months leading up to Anna Lambden, as well as her daughter's friend and a bystander who came to her assistance, receiving electric shocks on June 10.

The independent report, released on Friday, also reveals that two homeless people received shocks in the same place at the intersection of George Street and Ultimo Road a week earlier.

However, the investigation was unable to pinpoint with certainty who was responsible for the power cable becoming crushed by the lid of a traffic signal pit near Chinatown. It caused insulation around the wiring to wear away, opening the way for it to energise the pit lid.

Anna's mother, Viola Morris, said her daughter continues to be affected by injuries from the electrocution and the family remained “alarmed that pedestrian safety is put at risk”.