A 52-year-old man charged with the rape of young girls and making recordings now faces seven additional charges as a police investigation continues.

Equestrian Andrew Alan Williams was arrested in May along with his partner Laken Maree Rose, 29, and was charged with indecent assault and unlawful sexual connection with a child.

Williams appeared in Tauranga District Court on August 8 and has been charged with seven additional charges relating to two new, alleged victims. One is a three-year-old.

The charges include four counts of making objectionable publications, two counts of rape of a child under 12 years of age and one charge of possessing an objectionable publication.

Earlier this week his partner Laken Rose was also charged with nine new offences including making objectionable material showing the sexual violation of girls between five and 16 years old and two charges of sexual violation, as a party, of two girls aged three and five.

Detective Sergeant Darrell Brazier says the new charges were laid after police began reviewing a "vast quantity" of images and videos.

"In total there are about 150,000 images and videos and we are still making our way through them," he says.

"The new charges relate to two further alleged child victims.

"I've had to assign one of my investigators to look through these very concerning images."

Brazier says more charges could be laid as the investigation continues.

Williams will appear again on September 23 while Rose will appear on August 22.

-Stuff.co.nz