A radicalised white supremacist who was stockpiling homemade guns and expressed a desire to carry out a mass shooting at a NSW shopping centre could have been "the next Martin Bryant", a judge has said.

Michael James Holt, 26, pleaded guilty last year to manufacturing and possessing guns, knuckledusters and slingshots found at his mother's house in Windsor, his grandfather's house in nearby Hobartville and room five at the Tall Timbers pub hotel in Ourimbah.

Michael James Holt, who pleaded guilty to making and possessing prohibited firearms, expressed a desire to shoot up a shopping centre.

During a sentencing hearing in the NSW District Court on Friday, it was revealed that Holt has also pleaded guilty to possessing and disseminating child sexual abuse images uncovered following the 2015 raids.

More than 40 pages of text messages sent by Mr Holt included several that expressed a desire to kill, the court heard.