A Perth businessman accused of sexually abusing 24 children over several years has pleaded guilty to more than 400 charges.
The 47-year-old, who cannot be named for legal reasons, faced Perth Magistrates Court via videolink from prison on Wednesday.
He pleaded guilty to 413 charges, including sexually penetrating a child aged under 13 and producing child exploitation material.
A further 11 charges were discontinued.
The man was arrested last year after police searched his home and workplace, seizing computers and storage devices.
West Australian police allege about 3.8 million child exploitation videos and images were found on the devices, some of which allegedly showed him offending against the children.
He is alleged to have sexually abused 24 boys and girls, aged from three to 13, between 2015 and last year.
Detective Inspector Hamish McKenzie this month said it would be alleged the man knew the victims through family and friends.
"(It) is one of the most significant child abuse investigations ever conducted in Western Australia insofar as how many images were located and how many victims we will allege have been abused," Det Insp McKenzie told reporters.
The man was remanded in custody to face a pre-sentencing hearing in the District Court in June.