Queensland police have appealed for “extra vigilance” among young Justin Bieber fans after laying hundreds of extra charges against a man accused of posing as the singer to groom children online.

The man has been charged with 931 child sex offences after detectives allegedly uncovered a cache of new evidence in his computer.

The 42-year-old is accused of deceiving young victims from overseas into sending him explicit images by convincing them he was the Canadian pop star. Coincidentally, Bieber is currently on tour in Australia.

The man was charged on Thursday with rape, indecent treatment of children, using a carriage service to procure a child under 16 and making child exploitation material.

Police from the child protection task force Argos said the new charges followed a “thorough examination” of his laptop, which allegedly contained a large amount of child exploitation material indicating offending dating back at least a decade.

The man is accused of using Facebook, Skype and other online platforms to communicate with his victims.

Inspector Jon Rouse, from the anti-child exploitation task force Argos, said the investigation showed “both the vulnerability of children that are utilising social media and communication applications and the global reach and skill that child sex offenders have to groom and seduce victims”.

“The fact that so many children could believe that they were communicating with this particular celebrity highlights the need for a serious rethink about the way that we, as a society, educate our children about online safety,” Rouse said.

“I want to recognise the efforts and commitment of the investigative team at task force Argos to keeping children safe.”

He is due to appear in the Brisbane magistrates court on 6 April.