Douglas Hugh Stewart faces a maximum sentence of five years in prison. (CBC)

A judge says she needs some time to determine a sentence for a Moncton man who pleaded guilty to three charges involving what police described as the largest collection of child pornography in Canada.

Crown attorney Karen Lee Lamrock told CBC News that Douglas Hugh Stewart, 51, had almost six million images — pictures and videos — in his possession. In total, he had more than 4.7 million pornographic images and more than 1.2 million images of nude children and children in bathtubs.

On Thursday, Stewart pleaded guilty to two new charges — accessing and distributing child pornography. He pleaded guilty to a charge of possession in June.

Lamrock said Stewart has been collecting since the 1980s and that he looked for new material on a regular basis.

She said the analysis of images "completely overwhelmed RCMP" and that they had to add storage because all the RCMP servers were full. She also said it took 700 hours to categorize images.

The sentencing hearing was originally slated for Aug. 19, but provincial court heard his psychiatric evaluation had not yet begun due to a shortage of qualified professionals.

The Crown and defence had jointly recommended the psychiatric evaluation to help determine Stewart's risk of reoffending and assist Judge Anne Dugas-Horsman in sentencing.

The indictable offence carries a maximum sentence of five years in prison and a minimum of 45 days in jail.

Stewart was arrested March 23 as part of Operation J Treasures, a joint police investigation into peer-to-peer computer file sharing of child sexual abuse images in New Brunswick.

Two other men and a male under age 18 were also arrested after search warrants were executed in Havelock, Dumfries and Grand Bay-Westfield.

Investigators seized a variety of computers and related equipment.

Record number of images

Lamrock said the "sheer magnitude [of number of images] has never been dealt with in Canadian courts."

The Crown wants Stewart to spend five to seven years behind bars and wants Stewart to be a registered sex offender for life.

Defence lawyer Maurice Blanchard asked the court for four years in prison. Stewart has already served seven months in jail.

Blanchard said Stewart acknowledged he has an illness and compulsion and said he wants treatment. He also pointed out in court that he has co-operated with police. He asked that all of that be taken into consideration.

Stewart had no prior criminal record.

The Atlantic Region Integrated Technical Crime Unit, Codiac Regional RCMP, Fredericton police, the National Child Exploitation Co-ordination Centre and RCMP districts throughout the province assisted in the investigation, which began in November 2010.

Dugas-Horsman said she needs time to go through all of the material associated with the case and will give a written decision on Nov 14.