A 42-year-old Australian man has been charged with committing more than 900 child-sex offenses after he was accused of pretending to be the pop star Justin Bieber to solicit explicit online photographs from children, the Queensland Police Service said on Thursday.

The police said that the victims included dozens of Mr. Bieber’s fans in Australia, Britain and the United States. The 23-year-old Canadian pop singer, whose rise to stardom was driven in large part by support from adoring young fans, is on tour in Australia.

The suspect, who has not been identified by name, was already facing charges in Queensland State of possessing material exploiting children, and of using the internet and social media to entrap children under age 16, the police said.

He now faces a further 931 criminal charges for offenses including rape, the indecent treatment of children and “making child-exploitation material” that the police said stretched back at least a decade.