Cpl. Derrick Gallagher was charged earlier this month with eight counts of sexual assault and two counts of voyeurism.
Police said Thursday that he has been charged with nine more counts of voyeurism, eight more counts of sexual assault and one count of assault.
Police say the new charges relate to 10 more alleged victims.
Gallagher appeared in court in Pembroke, Ont., via video Thursday and he will make another video appearance in a week.
Police have released a photo of Gallagher and his tattoos and are urging females who have "been in his company" to contact the Upper Ottawa Valley OPP detachment.
OPP spokeswoman Sgt. Kristine Rae said they are looking to identify more than 50 other women who may have been in contact with Gallagher.
"There's several women out there that we don't know where they're from, and we know this is expanding," she said.
(The Canadian Press, myFM)