The 24-year-old woman was also allegedly attacked by a group of juveniles in the Cairns CBD when she tried to raise the alarm on Wednesday morning.
"It does sound like a very disturbing story," Queensland Premier Steven Miles told reporters on Thursday.
"I understand the police have acted swiftly and apprehended the alleged offender."
Police said the woman was walking past the boy in the Cairns city centre when he allegedly sexually assaulted her.
She called the police before being set upon by the 10-year-old, along with three other juveniles, police allege.
The woman suffered minor bruising and scratches to her head and face.
"No doubt a traumatic experience for the young lady," Detective Inspector Kevin Goan told reporters.
"The young age of the offenders is abhorrent. People are entitled to go about their business in our community."
Officers responded to a report of an assault on the corner of Lake and Shields streets after 10am, police said.
The boy was arrested along with three other youths "within minutes", with all four known to police.
The 10-year-old was charged with sexual assault, common assault and assault occasioning bodily harm whilst in company.
Police said no one else had been charged, but the investigation was continuing.
16°C