10/03/2017 10:22 AM AEDT | Updated 10/03/2017 11:57 AM AEDT

Former QUT Law Lecturer Allegedly Posed As Justin Bieber To Exploit Children

He's expected to appear in court in April.

A man who allegedly impersonated Justin Bieber to commit more than 900 child sex offences is a former law lecturer from the Queensland University of Technology who was first arrested four months ago.

Police allege Gordon Douglas Chalmers posed as the Canadian pop star on Facebook and Skype to persuade fans to send him explicit images.

Chalmers, 42, was first arrested in November last year, and on Thursday authorities charged him with an additional 931 child sex offences including indecent treatment of children and making child exploitation material.

He was sacked by QUT in November last year.

A large amount of child exploitation material was allegedly seized from his computer, and it's alleged his offending dates back to at least 2007, Police have said.

They have asked Justin Bieber fans and their parents to be extra vigilant when using the internet.

The pop star is in Australia as part of his Purpose tour, and is expected to perform in Queensland on Monday.

The investigation was headed up by Task Force Argos, a unit which works to track down people using the internet to commit child sex offences.

Chalmers is expected to appear in Brisbane Magistrates Court on April 6.