He claims children worked day and night, with some getting upset amid threats they'd be "sent back to China".
"Any reasonable person who looks at the broad facts of this case will feel a degree of discomfort and concern."
Zirka Circus is now in liquidation - but the former owners Jeni and Judy Hou dispute the allegations.
"The inherent problem with this is it's about suspected abuse, so it's always going to be a grey area."
Mandatory reporting is one of the recommendations from the review into the death of five-year-old Malachi Subecz.
Independent review revealed gaps in the system by agencies.
"By removing this policy, parents will have more flexibility to spend more time with their children."
