"We are investigating issuing proceedings against the Melbourne Show and the ride operator. It will be an action in negligence," Munir said.
WorkSafe has determined the ride is safe and given approval for it to re-open.
The news follows a video of the crash surfacing on social media. The man who unintentionally captured the moment Rodden was struck by the roller-coaster says he is having trouble sleeping.
"All of a sudden, I saw someone getting taken up but at the same time I'm thinking 'f***, my sister, my partner," he told 7News.
"But you can see she'd bent down to pick something up. I don't know if it was a phone or what, but she was so fixated on picking it up that she didn't even see the ride at all."
The footage was passed on to Victoria Police as part of their investigation.
Shylah Rodden was hit by a rollercoaster at the Royal Melbourne Show and suffered critical injuries. Photo / Supplied
A Melbourne Royal Show spokesperson said: "The safety and wellbeing of our visitors to the Show continue to be our number one priority.
"We uphold strict safety protocols in line with Victorian WorkSafe regulations and all rides on site have undergone stringent compliance inspections.
"No ride is turned on until it has passed all the required safety and compliance documentation."
Show chief executive Brad Jenkins called the accident "tragic".
"From our understanding, there was a mobile phone at the base of the Rebel Coaster that she dropped on the ride and she went back to recover the mobile phone," he said.
"Regrettably, she was tragically struck by the cart coming down."
