One child sexually harmed every two hours

Every two hours in Australia, a child is sexually harmed, according to child protection advocacy group Bravehearts.

The group is highlighting this alarming statistic ahead of its 20th White Balloon Day.

"It is likely there is a child in everyone's life, or the life of someone they know, who has been a victim of child sexual assault," Bravehearts founder Hetty Johnston said.

She said one in five Australian children would be sexually assaulted in some way before their 18th birthday.

"White Balloon Day is about encouraging people from all corners of the community to step up for these kids, raising awareness and funds to enable the continued delivery of vital support and prevention programs, while giving kids the confidence to come forward and break the silence," she said.

White Balloon Day is on September 9.